Coughing in Horses Explained: What It Means and How to Help

A coughing horse is rarely just clearing its throat. Coughing in horses is a clinical sign, not a diagnosis, and the useful question is never simply whether the horse coughed but when, how often, and what else is going on. A single cough as you pick up the reins after the horse has stood in for a few hours is usually unremarkable. A horse that coughs repeatedly at rest, coughs its way through every schooling session, or coughs alongside a temperature and nasal discharge is telling you something that needs acting on.

This guide covers what a cough means, the causes that actually turn up on UK and South African yards, how to triage before you pick up the phone, the red flags that make it a same-day call, what is and is not worth giving a coughing horse, and the environmental management that prevents most chronic coughing in the first place. It is written for people who keep horses, not for people who market to them, and it stops short of anything that belongs to your vet.

One framing point before the detail. Coughing is a specific sign of respiratory disease but not a sensitive one: a coughing horse almost certainly has something going on in its airways, but plenty of horses with significant airway inflammation never cough at all. That asymmetry matters. It means a cough should always be taken seriously, and it also means the absence of a cough is weak reassurance in a horse that is losing performance.

What a Horse's Cough Actually Tells You

The cough is a forceful expulsion of air that clears the airways of mucus, inhaled material or irritants. Horses cough less readily than people, and there is an anatomical reason for it: horses are obligate nasal breathers, so they cannot switch to the mouth to clear an airway, and the reflex has to do all the work. By the time a horse coughs, the airway has produced enough irritant or mucus to override the swallowing reflex that quietly handles small amounts all day.

The character of the cough is worth noting, though it is a starting point rather than a diagnosis. A productive cough that brings up mucus is doing useful mechanical work. A dry, harsh, repeated cough more often reflects inflammation without enough mucus to shift. Neither pattern reliably separates viral from bacterial from allergic disease on its own, which is why the timing and the accompanying signs carry more diagnostic weight than the sound.

The honest line between normal and abnormal is less precise than most articles pretend. There is no validated coughs-per-minute threshold that separates a healthy horse from a sick one. What experienced yard staff and vets actually use is a pattern judgement: an isolated cough at the start of work in an otherwise well horse is common and usually unremarkable, whereas coughing that recurs day after day, persists through exercise, happens at rest, or appears alongside any other sign is worth investigating.

Quick Triage: Matching the Cough to the Cause

Timing is the single most useful piece of information you can gather before ringing the vet, because it narrows the list faster than anything else. This table is a starting point for the conversation, not a substitute for it.

When the cough happens	Most likely explanations	How urgent
One or two coughs at the start of work only	Residual mucus being cleared after standing in	Routine. Note it and watch the pattern.
Throughout exercise, getting worse as work goes on	Mild to moderate equine asthma, airway inflammation	Book a routine vet visit.
Specifically while eating hay	Dust or mould spores in the hay, or hay quality	Change the forage first, then reassess.
In the stable, but clear at grass	Environmental allergen response, the classic asthma pattern	Manage the environment. Vet if it persists.
At grass in summer, but clear when stabled	Summer pasture-associated equine asthma	Book a routine vet visit.
Sudden onset with fever and dullness, often several horses at once	Equine influenza, EHV, strangles or another infection	Isolate the horse and ring the vet the same day.
Immediately after fast work, sometimes with blood at the nostril	Exercise-induced pulmonary haemorrhage	Speak to your vet before the next fast work.
While eating, with feed or saliva at the nostrils and repeated swallowing	Choke, which is an oesophageal problem rather than an airway one	Same-day emergency call.

The Main Causes of Coughing in Horses

Causes divide broadly into infectious, allergic or environmental, and a smaller group of mechanical and miscellaneous problems. On most UK and SA yards the first two account for the overwhelming majority of cases, and the single commonest cause of a long-running cough in an otherwise well horse is equine asthma.

Equine Asthma: The Most Common Chronic Cause

Equine asthma is the current umbrella term for the airway disease previously split between recurrent airway obstruction (RAO), inflammatory airway disease (IAD), chronic obstructive pulmonary disease and the yard word heaves. The renaming came out of a veterinary consensus process that deliberately aligned equine terminology with human respiratory medicine, and the substantive change was not cosmetic: the old labels implied separate diseases, whereas the current view treats them as points on one spectrum of airway inflammation.

Two ends of that spectrum are described:

• Mild to moderate equine asthma, formerly inflammatory airway disease. A cough, often with increased mucus and a loss of performance that owners describe as the horse simply not feeling right. Common in young performance horses. Frequently reversible with management change alone.
• Severe equine asthma, formerly RAO or heaves. Persistent coughing, visibly increased breathing effort at rest, and in long-standing cases a heave line, which is the ridge of hypertrophied abdominal muscle that develops along the flank from chronic expiratory effort. Predominantly older horses.

The triggers are inhaled: mould spores and respirable dust from hay and straw are the dominant ones in a UK stable. This is why equine asthma is both the most common chronic cause of coughing and the one most responsive to changes you can make yourself, without a prescription. The equine asthma reference entry covers the clinical picture in more depth.

Equine Influenza

A highly contagious viral respiratory disease and the classic cause of a cough running through a whole yard. Onset is abrupt: a horse can go from normal to febrile, dull and off feed inside a day, followed by a dry, hacking cough that commonly persists for two to three weeks even where the illness itself was mild. Vaccination substantially reduces both the likelihood and the severity of disease but does not guarantee protection, so flu stays on the list for a coughing horse on a vaccinated yard. Competition bodies set their own booster intervals and these are stricter than the standard annual cycle, so check the current rule for your discipline rather than assuming. See our guides to equine influenza and horse vaccinations, and the equine influenza reference entry.

Equine Herpes Virus (EHV-1 and EHV-4)

Presents much like flu, with fever, nasal discharge and a cough. The reason EHV is treated more seriously than its respiratory signs alone would justify is that EHV-1 can also cause abortion in pregnant mares and, less commonly, a neurological form. Suspected cases mean immediate isolation and a vet call, and confirmed outbreaks trigger movement restrictions imposed by the relevant competition authority rather than by government. More detail in the equine herpesvirus reference entry.

Strangles

A bacterial infection caused by Streptococcus equi subspecies equi. The signature signs are thick purulent nasal discharge and abscessation of the lymph nodes under the jaw and at the throatlatch, but a cough is present in many cases, particularly early, and a coughing horse with a snotty nose and any swelling under the jaw should be isolated before anything else happens. Diagnosis is by laboratory testing, and the disease is extremely contagious.

A point worth being precise about, because it is widely muddled: strangles is not a notifiable disease in the United Kingdom. You can check the current statutory list on the government notifiable diseases collection. What does exist is voluntary surveillance and reporting, which is what makes national case numbers visible at all, and which depends on yards and vets choosing to report. Voluntary reporting is genuinely worth doing, but it is not a legal obligation and it should not be described as one. Our full guide to strangles in horses and the strangles reference entry go further, and equine disease surveillance reporting publishes the aggregate picture.

Summer Pasture-Associated Equine Asthma

A seasonal variant in which the horse coughs and struggles at grass in warm weather, driven by inhaled pollens and outdoor moulds rather than stable dust. The tell is that the pattern inverts: these horses often improve when brought in, which is the opposite of the classic stabled asthma case and a useful discriminator when you take the history. It overlaps with what owners describe as hay fever in horses. Diagnosis rests on a careful seasonal history, so keeping a simple diary of when the cough is present pays for itself.

The Post-Viral Cough

Worth its own heading because it causes so much confusion. A cough that outlasts the viral illness that started it is common, and it can persist for weeks after the horse is bright, eating and apparently well. The difficulty is that a lingering post-viral cough and early equine asthma look similar from the outside, and a horse pushed back into work while its airways are still inflamed is exactly the horse that develops a chronic problem. If a cough is still there several weeks after a viral illness has otherwise resolved, it has stopped being a post-viral cough you can wait out and become something to investigate.

Lungworm

Infection with Dictyocaulus arnfieldi, typically picked up from pasture shared with donkeys, which are the natural host and often carry it without signs. It produces a persistent cough that mimics equine asthma closely, with one very useful difference: it does not improve when you fix the environment. A horse whose cough is unchanged after a genuine switch to steamed forage and low-dust bedding deserves to have lungworm considered. Diagnosis and treatment are straightforward once it is on the list. See the equine worm infestations reference entry.

Choke

Oesophageal obstruction, most often from bolted dry feed or unsoaked sugar beet. It belongs here only because owners meet it as coughing, but the mechanism is different: the food is stuck rather than the airway being inflamed. The distinguishing signs are saliva and feed material at both nostrils, repeated unsuccessful swallowing, and an anxious, stretched-out neck. Treat it as an emergency and ring the vet. More in the equine choke reference entry.

Pneumonia and Pleuropneumonia

Serious lower respiratory infection, classically associated with long-distance transport, with aspiration, or with an already compromised horse. The cough is only one part of a picture that includes fever, marked dullness, rapid shallow breathing and a reluctance to move. This is a veterinary emergency and not a wait-and-see. See the equine pneumonia reference entry.

Exercise-Induced Pulmonary Haemorrhage

Bleeding from the pulmonary circulation into the airways during intense work. It is common in racehorses and seen in other horses doing fast work. Most affected horses show nothing visible externally, and blood at the nostril is the exception rather than the rule, which is why endoscopy after work is how it is usually confirmed. A horse that coughs consistently at the end of fast work is worth investigating for it. Medication used for EIPH in some racing jurisdictions is prohibited on raceday under British racing rules, so in a UK context the practical levers are environmental and training-based, and any medication question is one for your vet against the current rules of your discipline.

Yard Triage: Reading the Cough

Your vet is going to ask all of the following. Having the answers ready shortens the diagnostic process considerably and often decides whether the visit is today or later in the week.

Before you ring, check and write down

• Temperature. Take a rectal temperature. Normal for an adult horse is 37.5C to 38.5C, the range the British Horse Society gives. Anything above 38.5C alongside a cough should be treated as an infection until proved otherwise, and so should a significant rise from that particular horse's own normal. Our guide to taking a horse’s temperature, pulse and respiration covers the method.
• Respiratory rate at rest. Normal is around 8 to 16 breaths per minute for an adult horse at rest. Count it before you disturb the horse, not after.
• Nasal discharge. Note which nostril or both, and the character: clear and watery, white and mucoid, yellow or green, blood-tinged, or thick and foul-smelling.
• Lymph nodes. Palpate under the jaw and at the throatlatch. Swelling here raises the index of suspicion for strangles sharply.
• Breathing effort. Look for nostril flare, abdominal effort on breathing out, and a heave line along the flank.
• Appetite and demeanour. Off feed, dull, or standing apart from the others all point towards infection.
• The rest of the yard. Any other coughing horses, any recent arrivals, any horses back from a show or a sale.
• The pattern over time. When did it start, is it getting better or worse, and what makes it better or worse.

The Dry Cough With No Other Symptoms

This is one of the most commonly searched versions of the problem and one of the least well covered: the horse is bright, eating, has a normal temperature, and simply coughs. Nothing else is wrong.

It is genuinely reassuring that the horse is systemically well, and a horse in this category is very unlikely to have an acute infectious disease needing an emergency call. It is not, however, a reason to ignore it, because the two commonest explanations both reward early action:

1. Mild equine asthma. By definition this is the horse that coughs and is otherwise normal. It has no fever and no discharge because it is not an infection. Caught early it often resolves on management change alone. Left for a year it becomes much harder to reverse.
2. An environmental irritant that nobody has connected to the cough. A new batch of hay, a change of bedding, a move to a different stable, building work on the yard, a stable downwind of the muck heap. The cough is a straightforward response and it resolves when the exposure does.

The practical approach is to treat it as an experiment with a defined endpoint. Change the forage and the bedding properly, maximise turnout, give it two to three weeks, and keep a note of the cough. If it clears, you have both your diagnosis and your treatment. If it does not change at all, that null result is itself useful information and the horse needs a vet, with lungworm and early asthma both on the list.

The Horse That Coughs at Night

Owners often notice a cough is worse in the evening or overnight, or hear about it from someone doing late checks. That timing is informative rather than sinister.

• The horse has usually been standing in for hours, so the exposure to stable air, bedding dust and ammonia is at its cumulative peak.
• Night-time is when doors get shut and rugs go on, so ventilation is typically at its worst exactly when the horse is spending the longest continuous period inside.
• Ammonia accumulates from urine in the bed overnight, and it is a direct airway irritant in its own right, quite apart from any allergen.
• Horses are usually eating hay through the night, so a hay-associated cough shows up then and is easy to misread as a night-time pattern rather than a forage one.

A cough that is clearly worse overnight and better after a day at grass points strongly at the stable environment rather than at infection, and the response is the ventilation and bedding work described below rather than a vet visit in the first instance. If the horse is also febrile or dull, that changes and it becomes a same-day call regardless of the timing.

The Horse That Coughs While Eating

Coughing specifically tied to feeding splits into two very different situations, and telling them apart matters because one is routine and the other is urgent.

Coughing while eating hay, otherwise fine. This is almost always the forage. Dust and mould spores are released as the horse pulls at the hay, and they are inhaled directly at the source. It is the easiest version of the problem to fix: steam or soak the hay, switch to haylage, or move to a hay alternative. Feeding at ground level rather than from a raised hay net also helps, because it lets the airways drain and keeps the dust cloud away from the nostrils.

Coughing while eating with saliva or feed at the nostrils. This is not a forage quality problem, it is choke, and it is an emergency. The horse will make repeated unsuccessful swallowing attempts, often stand with the neck extended and look distressed. Take the feed away, do not attempt to give anything by mouth, and ring the vet immediately.

A third possibility worth keeping in mind if neither fits: dental problems and, in older horses, difficulty with the swallowing mechanism can both produce coughing at feeding. If a horse coughs at feed time and the forage change makes no difference, ask for the teeth to be checked.

Red Flags: When to Call the Vet Immediately

Ring the vet the same day if the cough comes with any of the following:

• A temperature above 38.5C. Not 39C, which is the figure this article used to give. The British Horse Society and Horse & Hound both put a raised temperature at above 38.5C, and in a coughing horse that is frequently the first sign of strangles or flu, before any nasal discharge appears.
• Refusal to eat or drink.
• Visible respiratory distress at rest, meaning flared nostrils, rapid or laboured breathing, obvious abdominal effort, or an anxious expression.
• Thick yellow, green or blood-stained nasal discharge, or a discharge that smells foul.
• Marked lethargy or weakness.
• Swollen lymph nodes under the jaw or at the throatlatch, especially with a snotty nose.
• Signs of choke, meaning saliva and feed at the nostrils with repeated swallowing attempts.
• More than one horse on the yard coughing, which raises the possibility of an infectious outbreak and changes what you should do about movement on and off the premises.

A routine, non-urgent appointment is appropriate for a cough that has gone on for more than a week or so in a horse that is otherwise eating, drinking and behaving normally, with no fever and no abnormal discharge. Do not simply keep waiting on that horse indefinitely, though. A cough that has been present for months without ever being investigated is how mild, reversible airway inflammation turns into established disease.

One yard-level point that is easy to forget in the worry about an individual horse: if you suspect an infectious cause, stop movement on and off the yard and isolate the affected horse before you do anything else. Isolation done in the first hour is worth far more than isolation done after the vet confirms it two days later, and it costs you nothing if you turn out to be wrong.

The Diagnostic Workup

What your vet does will depend on the history and the clinical signs. You are not expected to know which of these is appropriate, but knowing what they are and why they are done makes the conversation easier and the costs less surprising.

• Auscultation. Listening to the lung fields with a stethoscope, often with a rebreathing bag over the nose to deepen the breathing and make subtle abnormalities audible.
• Endoscopy. Passing a flexible endoscope up the nostril to inspect the upper airway, larynx and trachea directly, and to see how much mucus is present and where.
• Tracheal wash or bronchoalveolar lavage. Sampling fluid and cells from the lower airways for cytology and, where relevant, culture. This is the definitive test for equine asthma, because it looks at the inflammatory cell population rather than inferring it.
• Blood tests. A haematology panel for evidence of inflammation, and acute-phase proteins such as serum amyloid A, which rise quickly and can help distinguish an active infection.
• Nasal or nasopharyngeal swabs and PCR. For influenza, EHV and strangles specifically.
• Thoracic ultrasound or radiography. Where pneumonia or pleural disease is suspected.
• Faecal testing. Where lungworm is a possibility, though a negative result does not entirely exclude it in horses.

What to Give a Horse With a Cough

This is the most searched question on the topic and the one where the internet gives the worst answers, so it is worth being direct.

Do not give human cough medicine

Reaching for a bottle of human cough syrup is a common impulse and a bad idea. The reasons are practical rather than moralistic. Dosing is the obvious problem: a horse is many times the body mass of an adult human, so a human dose does nothing and a scaled-up dose is a guess with no safety data behind it. The larger problem is that many human cough and cold preparations are combination products containing decongestants, antihistamines, paracetamol or other actives, several of which have no established safety profile in horses at any dose.

There is a second issue that catches out competition riders in particular. Anything you give a horse can contain a prohibited substance, and a well-meant dose of something from the human medicine cabinet is a genuinely plausible route to a positive test. If the horse competes under any ruleset, nothing goes in without checking it against the current prohibited list.

The deepest problem, though, is conceptual. Suppressing a cough does not treat what is causing it. The cough is the airway clearing itself, and in a horse with mucus to shift, silencing the reflex is actively unhelpful. There is a reason your vet reaches for anti-inflammatories and airway management rather than cough suppressants.

What about honey, steam and essential oils?

These come up constantly and deserve a fair rather than a dismissive answer, because they are not all in the same category.

• Steam inhalation has a real rationale, and steaming forage is genuinely one of the most effective interventions available. Steaming the horse itself is a different proposition and is not something to improvise. Never confuse the two.
• Honey and syrups are palatable and harmless in small quantities, and if adding something sweet gets a reluctant horse to eat a soaked mash then it has done a job. What it is not doing is treating airway inflammation. Be aware too that the sugar content matters for any horse with metabolic concerns.
• Essential oils should be treated with real caution. Volatile compounds delivered into an already inflamed airway can irritate rather than soothe, concentrations in commercial products vary enormously, and the evidence base in horses is thin. This is not a neutral experiment on a horse that is already struggling to breathe.
• Herbal and licensed respiratory supplements vary widely. Some are reasonable adjuncts alongside proper management. None of them substitute for fixing the air the horse breathes, and if a product is being sold to you as an alternative to environmental change rather than an addition to it, that is a reason for scepticism.

What actually helps

The honest hierarchy, in descending order of how much difference it makes:

1. Fix the air. Forage, bedding and ventilation, covered in detail below. For equine asthma this is not the supporting act, it is the treatment.
2. Rest the horse appropriately if the cause is infectious, and resist the pressure to get back to work early.
3. Get a diagnosis if the cough persists, because the management for asthma, lungworm and a post-viral cough are not the same and guessing wastes months.
4. Prescription medication where your vet judges it necessary. Anti-inflammatory treatment and, in asthma cases, inhaled therapy delivered through a proper equine device can make a substantial difference. All of this is prescription-only, dose and duration are matters for your vet who has examined the horse, and none of it is a substitute for the first point on this list.

Deliberately absent from this article: specific drug names, doses and regimens. That is not squeamishness. Choosing between them depends on the diagnosis, the individual horse, what else it is on and what it competes under, and an article cannot do any of that. Ask your vet.

Environmental Management for the Coughing Horse

Whatever the diagnosis turns out to be, this is part of the plan, and for equine asthma it is most of the plan. The three targets are respirable dust, mould spores and ammonia.

Forage

Hay is the largest single source of respirable particles in most stables, and it is delivered straight to the nostrils. Interventions, roughly in descending order of effectiveness:

• Steaming in a purpose-built hay steamer. High-temperature steaming substantially reduces both mould spores and respirable dust without leaching nutrients the way soaking does. It is the most effective forage intervention available and the one to reach for in a confirmed asthma case.
• Soaking. Effective at reducing airborne dust because it weighs the particles down, and much less effective against mould. It also leaches water-soluble carbohydrate, though by a margin that varies enormously between different hays, which means soaking cannot be relied on as a way of making a given hay safe for a laminitis-prone horse without testing. Do not leave hay soaking for extended periods in warm weather, as bacterial growth becomes its own problem. See the nutrients in hay for what is being lost.
• Switching to haylage. The higher moisture content suppresses dust and spore release. It changes the energy and protein you are feeding, so the ration needs looking at as a whole rather than swapping bale for bale. Our guide to feeding and storing haylage covers the practicalities.
• Feeding at ground level. Lowering the head lets the airways drain and moves the horse out of the dust cloud that a raised hay net creates around its face.
• Watch how forage is made and stored. Bales that were baled damp or stored in a poorly ventilated barn develop mould from the inside, and the bottom layer of a stack is the usual culprit. How hay is made explains why.
• Consider the whole ration. Chaff, alfalfa and bagged feeds vary considerably in dust, and dust-extracted versions are worth the difference for a sensitive horse.

Bedding

Straw is the second major source of stable dust and, in damp conditions, of mould spores. For a coughing horse the bedding options worth considering are:

• Dust-extracted shavings. The standard UK alternative and a substantial improvement on straw. Our guide to selecting shavings for bedding covers the grades.
• Hemp. Very low dust, highly absorbent, and increasingly common.
• Wood pellets. Close to dust-free and very absorbent. More expensive to run and they need managing differently, but excellent for a severe case.
• Cardboard. Niche and not cheap, but about as low-dust as bedding gets.
• Rubber matting with a light bedding overlay. The lowest-dust arrangement of all, though the bed still has to be deep enough for the horse to lie down comfortably, and drainage and ammonia control become the thing to get right.

One point that gets missed: bedding the coughing horse well is undermined if the horse next door is on straw and the barn shares an airspace. Respirable particles do not respect stable partitions. On a barn yard the bedding conversation is a yard-wide one, not a single-stable one.

Ventilation

The most under-rated of the three and the cheapest to fix. The traditional response to cold weather is to shut everything up, and the result is a warm, humid box in which ammonia, dust and moisture all accumulate against the horse. Horses tolerate cold far better than they tolerate bad air, and a rug is a better answer to a cold night than a closed top door.

• Keep top doors and windows open wherever it is practical. A rugged horse in a draught-free but well-ventilated box is in a far better position than a warm one in stale air.
• Ventilation needs both an inlet and an outlet to work. Opening one door at one end of a barn moves very little air. Ridge or roof ventilation is what makes barn stabling work.
• Avoid siting horses downwind of the muck heap, and keep the heap well away from the stable block and the forage store.
• Muck out thoroughly and keep the bed dry, since ammonia comes from urine held in the bed rather than from the horse.
• Maximise turnout. Every additional hour outside is therapeutic and costs nothing. For a horse with stable-associated asthma, turnout is the single most effective change most owners can make immediately.
• Take transport seriously. Long journeys with the head tied high in a poorly ventilated lorry are a well-recognised risk for lower airway problems, so travel with as much ventilation as conditions allow and let horses lower their heads at rest stops.

Returning to Work After Respiratory Illness

Bringing a horse back too early is the commonest owner mistake in this whole area, and it is the route by which a straightforward viral cough turns into a chronic airway problem. The airways take considerably longer to recover than the horse takes to look well.

The recognised figure is a week of rest for every day the horse ran a temperature, with a minimum of three weeks whatever the fever did. That minimum is the one the Merck Veterinary Manual gives for influenza, and it exists because three weeks is roughly how long the mucociliary apparatus lining the airways takes to regenerate. Horse & Hound's veterinary advisor Karen Coumbe MRCVS puts the same thing a different way: complete rest, with no strenuous exercise until at least three to four weeks after the signs have gone. The shorter yard version, two days of rest for every day of clinical signs, is not a safe substitute and this article used to offer it as one: it would put a horse with three days of signs back into work inside a week. Three weeks is the floor, not the target, and your vet may well want longer.

1. Complete rest first, for as long as the illness warrants. Turnout is fine and better than standing in. Ridden work is not.
2. Then walking work only, in hand or ridden, for at least five to seven days.
3. Add trot for a further five to seven days before anything faster.
4. Introduce canter and faster work last, and build it gradually rather than testing the horse.
5. Watch for the cough at every stage. If it reappears, drop back to the previous stage for another week rather than pushing through. A cough that comes back on increased work is the horse telling you the airways are not ready.
6. Keep the environment optimised throughout recovery, not just while the horse is visibly ill.

For competition horses, allow a clear margin after the last clinical sign before competing rather than entering at the first opportunity. Check the current rules of your own discipline, since these differ and they change. The risk of going too early is not only a poor performance on the day but a horse that never quite comes right that season.

A Note on “Horse Cough” in Humans

A meaningful share of searches for a horse cough are not about horses at all. People use "a cough like a horse", "horse cough" or "barking cough" to describe a harsh, hoarse, seal-like cough in a person, most often a child, and they arrive at pages like this one by accident. Google’s own results for these queries drift between the two subjects, which is a reasonable clue that the confusion is widespread.

If that is why you are here: this article is about horses and will not help you, and a barking or seal-like cough in a child, particularly one with noisy breathing in or any difficulty breathing, is a reason to contact a doctor or NHS 111 rather than to keep reading. Nothing on this page transfers between the two species in either direction, and that includes the medicines.

Frequently Asked Questions

Should I be worried if my horse is coughing?

A single cough as work starts, after the horse has been standing in, is usually unremarkable. Be concerned if the cough recurs day after day, continues through exercise, happens at rest, or comes with nasal discharge, a raised temperature, dullness, loss of appetite or reduced performance. Treat it as urgent, meaning a same-day call, if the horse has a temperature above 38.5C, thick or discoloured nasal discharge, visible breathing difficulty at rest, or if several horses on the yard are coughing at once.

What is the best cough medicine for horses?

There is no over-the-counter cough medicine that reliably treats the underlying cause of a horse’s cough, and human cough medicines should not be given to horses at all. Effective treatment depends entirely on the cause: an infection needs rest and veterinary management, equine asthma needs environmental change and often prescription anti-inflammatory or inhaled therapy, and lungworm needs specific antiparasitic treatment. Suppressing the cough itself is rarely the goal, because the cough is clearing the airway. The most effective thing most owners can do without a prescription is change the forage, the bedding and the ventilation.

Why does my horse cough at the start of work?

One or two coughs as the horse moves off, after it has been standing in a stable, is normal. Increased airflow and movement shift mucus that has pooled while the horse was still, and the cough clears it. What is not normal is coughing that continues throughout the session, gets worse as work goes on, or takes longer to settle each week. That pattern suggests airway inflammation, most commonly mild equine asthma, and is worth investigating with your vet before it becomes established.

How long should a horse’s cough last?

A cough associated with a viral infection commonly persists for two to three weeks and sometimes longer, even once the horse is otherwise well again. A cough still present several weeks after everything else has resolved should not be written off as post-viral and needs investigating. A cough that has been present for months, in a horse that seems otherwise fine, is the classic presentation of mild equine asthma and is the one most likely to be reversible if it is addressed rather than tolerated.

What is the difference between equine asthma and heaves?

They are not two conditions. "Heaves" is the traditional yard name for what is now called severe equine asthma, previously also labelled recurrent airway obstruction (RAO) or chronic obstructive pulmonary disease. The terminology was consolidated so that mild to moderate equine asthma (formerly inflammatory airway disease) and severe equine asthma sit on a single spectrum rather than being treated as separate diseases. The practical consequence is that a mildly coughing horse is not in a different category from an obvious heaves case, it is earlier on the same continuum, which is a good argument for acting early. Our guide to treating heaves in horses goes into the management in detail.

Can a horse cough be caused by something other than the lungs?

Yes, and it is worth knowing. Choke produces coughing but is an oesophageal obstruction rather than an airway problem. Dental disease and difficulty swallowing can both cause coughing at feed time. Heart disease is an uncommon cause in horses but is not unheard of in older animals. A horse that coughs specifically around eating, and does not improve when the forage is changed, deserves a dental examination as part of the workup.

A cough is information. Most of the time it is the airways reporting on the air the horse is being asked to breathe, and most of the time the fix is in the forage, the bedding and the ventilation rather than in a bottle. The cases that are not environmental tend to announce themselves with a temperature, a discharge or a sick-looking horse, and those are the ones that need the vet today. For related reading, see our guides to heaves and equine asthma, equine influenza, strangles and checking a horse’s temperature, pulse and respiration, or the MSD Veterinary Manual on equine respiratory disease and the British Horse Society’s horse care and welfare guidance for wider background. BEVA maintains professional guidance for vets.