English
Drooling in horses is a normal physiological response, especially during eating, chewing, or anticipation of feed. However, excessive salivation may signal oral irritation, dental disease, swallowing difficulty, toxic plant exposure, or another underlying health concern.
Because saliva supports chewing, swallowing, and digestion, changes in how much saliva a horse produces or how well they manage it can provide important clues about their health. Some cases of excessive drooling are temporary and relatively harmless, while others require prompt veterinary evaluation, especially when drooling occurs suddenly or alongside other signs of illness.
For horse owners, understanding the possible causes of drooling can help guide appropriate monitoring, pasture checks, dental care, and decisions about when to call a veterinarian. The amount of saliva, how long the problem lasts, and whether the horse is eating and swallowing normally are all important factors to consider.
Recognizing common causes of excessive salivation, signs that may indicate a more serious problem, and practical management strategies can help owners respond appropriately and support their horse’s overall health.
Drooling in Horses
Drooling in horses describes saliva dripping or flowing from the mouth. It can range from a small amount of moisture around the mouth to excessive salivation (ptyalism) that wets the lips, chest, and forelimbs. [1][2]
Changes in normal salivation can provide valuable clues about a horse’s health. Saliva is a normal and important part of the digestive process, helping moisten food and support chewing and swallowing. Since horses naturally produce large amounts of saliva while eating, a small amount of moisture around the mouth is not unusual. [1][2]
Excessive drooling, however, may indicate that saliva is being produced in unusually large quantities or that the horse is unable to swallow normally. [1][2][3]
Excessive drooling is not a disease itself, but a clinical sign that something may be affecting the mouth, throat, esophagus, or other body systems. The severity of the problem can vary considerably, from temporary irritation caused by pasture plants to conditions that require prompt veterinary attention. [4]
Some cases of drooling are linked to harmless causes that resolve on their own. However, drooling can also indicate dental problems, injuries, toxic plant exposure, or underlying illness that requires diagnosis and treatment. [1][2][4][5]
The amount of saliva present, how suddenly the drooling develops, and whether other signs occur at the same time can all help narrow down the underlying cause.
Understanding why horses drool, the conditions that can cause excessive salivation, and the signs that may accompany it can help owners decide when simple monitoring is appropriate and when veterinary attention may be needed.
What's your top priority with your horse's health?
What's your top priority with your horse's health?
Why Do Horses Drool?
Saliva is produced continuously in the horse’s mouth and plays an important role in chewing, swallowing, and digestion. [1][2]
Drooling occurs when saliva accumulates in the mouth faster than it can be swallowed or when saliva cannot pass normally through the upper digestive tract. [1] This may happen if saliva production increases or if normal swallowing is disrupted. [1][5]
Pain, irritation, inflammation, or injury affecting the mouth and throat can interfere with the normal handling of saliva. [1][2] Conditions that affect swallowing can also allow saliva to collect and spill from the mouth. [1] As a result, excessive salivation is considered a clinical sign rather than a disease itself. [1][5]
The underlying cause may range from minor irritation to a more significant medical condition, making other symptoms important when determining why a horse is drooling. [1][2][5]
Common Causes of Drooling in Horses
Drooling can occur for many different reasons, ranging from minor irritation of the mouth to conditions affecting swallowing or the digestive tract. [1][2][5] Some causes are relatively harmless and resolve on their own, while others require prompt veterinary attention. [1][5]
Common causes of drooling in horses include: [1][2][5][6]
- Dental disease
- Foreign material in the mouth
- Choke, or esophageal obstruction
- Oral injuries
- Plant-related irritation or toxins
- Vesicular and infectious diseases
- Disorders affecting swallowing
These causes can look similar at first, so the horse’s appetite, ability to chew and swallow, pasture exposure, and any signs of illness are important clues.
Medical Conditions
Several medical conditions can cause drooling by interfering with chewing, swallowing, saliva movement, or comfort in the mouth and throat. These causes are important to distinguish because some, such as choke or infectious disease, may require urgent veterinary care.
Choke
Choke occurs when the esophagus becomes partially or fully blocked by feed or foreign material. Unlike choking in humans, equine choke does not block the airway, so affected horses can usually still breathe.
However, it is still a medical emergency because complications can include aspiration pneumonia and damage to the esophagus, including esophageal rupture. [7]
Choke commonly develops when horses eat concentrated feeds too quickly or fail to chew properly, allowing dry feed to become lodged in the esophagus. Drooling may occur because saliva, water, and feed cannot move normally from the mouth to the stomach. [7][8]
Oral Lesions
Oral lesions are sores, cuts, abnormal growths, or inflamed areas in the mouth, including the lips, cheeks, tongue, gums, and corners of the mouth. These painful areas can develop from dental problems, injuries, infections, equipment-related pressure, or exposure to irritating plants or substances. [9]
Drooling may occur when lesions make chewing or swallowing uncomfortable, or when irritation increases saliva production.
Horses with oral lesions may have other signs, including: [9]
- Redness
- Swelling
- Raw skin
- Reluctance to accept the bit
- Head tossing
- Changes in eating behavior
Equine Odontoclastic Tooth Resorption & Hypercementosis
Equine odontoclastic tooth resorption and hypercementosis, or EOTRH, is a painful dental condition that most often affects the canine and incisor teeth at the front of the mouth. It can involve multiple teeth and may damage the tooth roots, surrounding ligament, gums, and nearby bone. [10][11][12][13]
Drooling can occur when affected teeth and gums become painful, inflamed, or infected, making it difficult for the horse to bite, chew, or hold feed comfortably in the mouth. [14]
Plant-Related Causes of Excessive Salivation
Some of the most dramatic cases of drooling in horses are associated with pasture plants and plant-related toxins. [5]
In many cases, excessive salivation develops because a plant directly irritates the tissues of the mouth. In others, it occurs because of naturally occurring toxins or fungal compounds present on the plant. Although some causes are relatively harmless, others may be associated with more serious poisoning or illness. [5]
Signs of plant-related drooling can range from mild moisture around the lips to profuse salivation that wets the chest and forelimbs. [3][5]
Plants that commonly cause excessive salivation in horses include: [5]
- Red clover (Trifolium pratense): Infected with the fungus Rhizoctonia leguminicola, commonly called black patch disease. This is the classic cause of slobbers syndrome and is widely reported in areas of North America where clover grows in pastures and hay fields.
- White clover (Trifolium repens): Infected with Rhizoctonia leguminicola. Like red clover, infected white clover can contain slaframine, a compound that stimulates excessive saliva production.
- Alsike clover (Trifolium hybridum): Grows across many temperate regions of North America and Europe. Alsike clover consumption may be associated with excessive salivation. It is also associated with photosensitization and liver disease in horses, which are separate conditions with a different and still unknown cause.
- Buttercups (Ranunculus species): Fresh buttercups contain irritating compounds that can cause inflammation of the lips and mouth, resulting in drooling. They are commonly found in moist pastures throughout North America and Europe, and buttercup exposure can be a concern when horses graze affected fields.
- Foxtail grasses (Setaria species): The barbed seed heads can become lodged in the mouth and gums, causing irritation, ulceration, and excessive salivation. Foxtails are widespread across much of North America.
- Cheatgrass (Bromus tectorum) & other awned grasses: Sharp seed structures can injure oral tissues and contribute to drooling, particularly in dry western regions of North America.
Because many pasture plants look similar, identifying the exact cause of plant-related drooling may require examination of both the horse and the pasture environment. Recent changes in grazing areas, pasture quality, or hay sources can provide important clues to the cause of excessive salivation. [5]
Table 1. Common causes of drooling in horses
| Cause | What owners may notice | Why it causes drooling | When to call a veterinarian |
|---|---|---|---|
| Dental disease |
|
|
|
| Foreign material in the mouth |
|
|
|
| Choke or esophageal obstruction |
|
|
|
| Oral injuries or ulcers |
|
|
|
| Plant-related irritation or toxins |
|
|
|
| Vesicular or infectious disease |
|
|
|
| Swallowing disorders |
|
|
|
When Is Drooling a Cause for Concern?
Drooling may occur on its own, but it is often accompanied by other signs that can help identify the underlying cause. [1][2][5]
Signs that may accompany drooling include: [1][2]
- Difficulty chewing
- Quidding, where partially chewed feed is dropped from the mouth
- Reduced appetite or reluctance to eat
- Bad breath associated with dental disease or oral infection
- Weight loss
- Oral ulcers, wounds, or other visible lesions
Not all cases of drooling indicate a serious problem. However, veterinary attention is recommended when drooling is accompanied by signs that suggest pain, illness, injury, or difficulty swallowing. [1][2]
When to Call the Veterinarian
Call a veterinarian if drooling is sudden, severe, persistent, recurrent, or occurs with signs that the horse may not be able to chew, swallow, or manage saliva normally. Prompt evaluation is especially important when drooling may be related to choke, oral injury, infectious disease, toxic plant exposure, or neurological dysfunction. [1][2][5][6]
Signs that warrant veterinary evaluation include: [1][2][5][6]
- Difficulty swallowing or an inability to swallow normally
- Feed material or saliva coming from the nostrils
- Repeated gagging, coughing, or unsuccessful attempts to swallow
- Sudden refusal to eat or drink
- Visible wounds, swelling, ulcers, or other abnormalities of the mouth
- Signs of choke or suspected esophageal obstruction
- Fever, lethargy, or other signs of systemic illness
- Neurological abnormalities such as weakness, incoordination, or difficulty controlling the tongue and lips
- Known or suspected exposure to toxic plants or other poisonous substances
A veterinarian may examine the mouth, teeth, throat, and overall health status to help determine whether the problem is dental, mechanical, infectious, toxic, or neurological. In some cases, diagnostic testing or emergency care may be needed, especially if the horse cannot swallow normally or shows signs of systemic illness.
Persistent or recurrent drooling should also be investigated, particularly when no obvious cause is present. [1][2]
Prevention & Management of Drooling in Horses
Preventing drooling in horses depends largely on reducing the risk of the conditions that commonly cause excessive salivation. While not all cases can be prevented, good management practices can help maintain oral health and reduce exposure to potential hazards. [1][2][5]
Routine dental care is one of the most effective preventive measures. [2] Regular oral examinations can identify sharp enamel points, fractured teeth, periodontal disease, and other abnormalities before they interfere with chewing and swallowing. [2]
Pasture and grazing management can also reduce the risk of excessive salivation. [5] Fields should be monitored for toxic plants and other oral irritants, while hay should be inspected for weeds, coarse seed heads, and foreign material that could injure oral tissues. Particular attention should be paid to clover-rich pastures during conditions that favor fungal growth associated with slobbers syndrome. [2][5]
Forage quality is also important. Choosing clean, appropriate hay and checking new forage sources for weeds, mold, coarse awns, or foreign material can help reduce the risk of oral irritation and toxic exposure. These checks fit naturally into a hay selection routine and broader forage management program. [2][5]
Management of drooling depends on identifying and treating the underlying cause. Dental disease, oral injury, infection, choke, and toxic exposure each require different approaches. [1][2][5]
Because drooling is a clinical sign rather than a disease itself, successful management focuses on resolving the condition responsible for the excessive salivation. [1][5]
Frequently Asked Questions
Here are some frequently asked questions about drooling in horses:
A horse may be drooling because saliva is being produced in excess or because the horse cannot swallow saliva normally. Common causes include dental disease, mouth injuries, foreign material in the mouth, choke, swallowing problems, plant irritation, toxic plant exposure, and fungus-infected clover. The seriousness depends on how suddenly the drooling starts, how much saliva is present, and whether the horse is eating, drinking, and swallowing normally.
Drooling in horses can be normal in small amounts, especially while eating, because saliva helps moisten feed and support chewing and swallowing. Excessive drooling is different because it may mean saliva is being produced in unusually large amounts or the horse is not managing saliva normally. Moisture around the mouth after eating is usually less concerning than sudden, persistent, or profuse salivation. Drooling should be assessed with the horse's appetite, comfort, behaviour, and ability to swallow.
Drooling in horses is not always serious, but it should be assessed alongside the horse's overall condition. Mild drooling from fungus-infected clover may resolve once the horse is removed from the source. Drooling is more concerning when it occurs with difficulty swallowing, feed or saliva coming from the nostrils, refusal to eat, fever, depression, visible mouth wounds, or neurological signs. Sudden, severe, persistent, or recurrent drooling should be evaluated by a veterinarian.
Clover can make horses drool when it is infected with the fungus associated with slaframine toxicosis, commonly called slobbers. Red clover and white clover are commonly involved, and affected horses may produce large amounts of saliva while otherwise appearing fairly normal. Alsike clover may also be associated with excessive salivation and other toxic effects in horses. Clover-rich pastures or hay should be checked carefully, especially when conditions favor fungal growth.
Slobbers in horses is excessive salivation caused by eating clover infected with a fungus that produces slaframine. The horse may drool heavily enough to wet the lips, chest, and forelimbs. Although slobbers can look dramatic, it may improve after the horse is removed from the affected pasture or hay source, provided no other signs of illness are present. If drooling is severe or occurs with depression, fever, poor appetite, or other abnormal signs, veterinary guidance is recommended.
Plants that can cause drooling in horses include fungus-infected red clover, white clover, alsike clover, buttercups, foxtail grasses, cheatgrass, and other awned grasses or irritating weeds. Some plants stimulate excessive saliva production, while others irritate or injure the lips, gums, tongue, and mouth. Buttercups can irritate oral tissues, while foxtail and awned grasses can lodge in the mouth and cause ulceration. Because many pasture plants look similar, recent changes in pasture, hay, or grazing areas can help identify the cause.
Dental problems can cause a horse to drool when pain or oral disease interferes with normal chewing and swallowing. Sharp enamel points, fractured teeth, periodontal disease, oral ulcers, infections, and painful front-tooth conditions such as EOTRH can all contribute to excessive salivation. Drooling with quidding, bad breath, weight loss, reduced appetite, or difficulty chewing may point toward a dental or oral cause. Persistent or recurrent drooling should be investigated with an oral and dental examination.
Choke can cause drooling in horses because an obstruction in the esophagus prevents saliva, water, and feed from passing normally toward the stomach. Signs may include repeated swallowing attempts, coughing, distress, sudden refusal to eat, and feed or saliva coming from the nostrils. Unlike choking in people, equine choke usually does not block the airway, so the horse can often still breathe. Suspected choke requires prompt veterinary attention because complications can include aspiration pneumonia, esophageal injury, or rupture.
Feed or saliva coming out of a horse's nose can indicate that the horse is not swallowing normally. This is a warning sign often associated with choke or another problem affecting passage through the throat or esophagus. A horse with nasal discharge containing feed or saliva may also cough, gag, refuse feed, or make repeated unsuccessful swallowing attempts. Contact a veterinarian promptly if these signs occur.
Mouth injuries or ulcers can make a horse drool by causing pain, inflammation, and irritation inside the mouth. Lesions may affect the lips, cheeks, tongue, gums, or corners of the mouth, making chewing or swallowing uncomfortable. Horses may also show redness, swelling, raw tissue, reduced appetite, head tossing, or reluctance to accept the bit. Visible wounds, swelling, ulcers, bleeding, or signs of infection should be assessed by a veterinarian.
Infectious disease can cause drooling in horses when it produces painful oral lesions, ulcers, blisters, fever, or systemic illness. Vesicular and inflammatory diseases can damage tissues in the mouth and make eating or swallowing uncomfortable. Drooling with fever, depression, visible mouth abnormalities, or other signs of illness is more concerning than drooling alone. Prompt veterinary evaluation is important when infection is suspected.
If your horse starts drooling, first check for signs such as difficulty chewing, quidding, reduced appetite, feed or saliva from the nostrils, coughing, mouth wounds, swelling, fever, depression, or abnormal tongue and lip control. Look at the horse's hay, pasture, and recent feed sources for clover, irritating weeds, coarse seed heads, mold, foreign material, or other hazards. Also consider whether the horse recently changed pastures, hay sources, feed type, or turnout areas. If the drooling is severe, sudden, persistent, or accompanied by signs of pain, illness, or swallowing difficulty, contact a veterinarian.
A veterinarian should be called for a drooling horse if the drooling is sudden, severe, persistent, recurrent, or occurs with other signs of illness. Warning signs include difficulty swallowing, feed or saliva from the nostrils, suspected choke, refusal to eat or drink, fever, depression, visible mouth wounds, swelling, ulcers, or neurological abnormalities. Veterinary evaluation is also recommended when toxic plant exposure is known or suspected. A veterinarian may need to examine the mouth, teeth, throat, and overall health status to identify the cause.
Drooling in horses can go away on its own when the cause is mild, temporary, and removed, such as exposure to fungus-infected clover. However, drooling should not be ignored if it persists, recurs, worsens, or appears suddenly without an obvious explanation. Any drooling linked with pain, illness, mouth injuries, swallowing difficulty, or changes in appetite should be investigated. Monitoring is most appropriate only when the horse is otherwise bright, eating normally, and no red flags are present.
Drooling in horses is treated by identifying and addressing the underlying cause. Dental disease may require corrective dental care, oral injuries or infections may need veterinary treatment, choke requires veterinary management, and plant-related drooling may improve after the horse is removed from the affected forage or pasture. Treatment differs because drooling is a clinical sign rather than a disease. Successful management depends on resolving the condition causing the excessive salivation.
Drooling in horses can be prevented in some cases through routine dental care, careful pasture monitoring, and safe forage management. Regular oral examinations can help detect sharp enamel points, fractured teeth, periodontal disease, and other abnormalities before they interfere with chewing and swallowing. Inspecting hay and pasture for toxic plants, clover with fungal growth, coarse seed heads, weeds, mold, and foreign material can reduce exposure to common causes of mouth irritation and excessive salivation. Not all cases can be prevented, but good management reduces several common risks.
Hay or pasture quality can affect drooling in horses when forage contains irritating plants, coarse seed heads, weeds, mold, clover with fungal growth, or foreign material. Foxtail, cheatgrass, and other awned grasses can injure oral tissues, while fungus-infected clover can stimulate excessive saliva production. New forage sources should be checked carefully if drooling begins after a hay change or turnout change. Clean, appropriate forage helps reduce the risk of oral irritation and plant-related salivation.
A horse can drool because it cannot swallow properly if a problem affects the throat, esophagus, or nervous control of the mouth and tongue. Swallowing disorders may cause saliva to pool or spill from the mouth instead of moving normally into the digestive tract. Signs may include difficulty swallowing, poor tongue or lip control, weakness, incoordination, or feed and saliva coming from the nostrils. These signs warrant prompt veterinary attention because they may indicate a serious underlying problem.
Summary
Drooling, or ptyalism, in horses refers to excessive saliva loss from the mouth and can range from mild moisture around the lips to heavy salivation that wets the chest or forelimbs.
- Saliva is important for chewing, swallowing, and digestion, so changes in salivation may indicate irritation, dental disease, swallowing difficulty, toxic plant exposure, or another health concern
- Common causes of drooling include dental problems, foreign material in the mouth, choke, oral injuries, infectious disease, plant-related irritation, toxins, and swallowing disorders
- Ptyalism may also occur after exposure to irritating or toxic plants
- Veterinary attention is needed if drooling is sudden, severe, persistent, recurrent, or occurs with other signs of pain or illness
- Prevention and management focus on regular dental care, pasture and feed management, and treating the underlying cause of excessive salivation
References
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