Foods Horses Should Never Eat: A Vet-Approved Guide

Knowing which foods horses should never eat is an important part of keeping them healthy. While many fruits and vegetables can be offered as occasional treats, others can upset the digestive system or contain compounds that are harmful to horses. Because horses cannot vomit, eating the wrong food may have more serious consequences than many owners realize.

Understanding which foods are unsafe and recognizing when accidental ingestion becomes a veterinary concern can help protect your horse from preventable illness.

Foods Horses Should Never Eat at a Glance

Not all unsafe foods pose the same level of risk. Some contain toxins that should never be fed, while others are more likely to cause digestive upset or other health problems if eaten in large amounts. The table below provides a quick overview before each food is discussed in more detail.

Why Some Human Foods Affect Horses Differently

Horses did not evolve to eat the same foods as people. Their digestive system is designed to process a forage-based diet made up primarily of grasses and hay. Unlike humans, horses are hindgut fermenters, relying on billions of beneficial microbes in the cecum and large colon to break down fiber and produce nutrients.

Foods that are high in starch, sugar, fat, or certain plant compounds can disrupt this delicate digestive system or expose horses to substances they are not adapted to metabolize. When large amounts of starch escape digestion in the small intestine, they enter the hindgut, where they can alter the normal microbial population and fermentation process. This disruption may increase the risk of digestive disturbances, including colic and other gastrointestinal problems.

Unlike many other animals, horses cannot vomit. Harmful foods cannot simply be expelled from the stomach after they are eaten, making accidental ingestion potentially more serious.

As a result, even foods that are harmless for people may cause digestive upset, toxicity, or other health problems in horses. This is why veterinarians recommend keeping a horse’s diet centered on forage and introducing any new treats gradually.

A visual explanation of the horse digestive system showing the difference between healthy forage digestion and the risks of feeding large amounts of starch or processed foods.

Foods That Are Toxic to Horses

Some foods should never be fed to horses because they contain compounds that can damage red blood cells, affect the nervous system, or cause other serious health problems. While the severity depends on the food consumed, the amount eaten, and the individual horse, these foods should always be kept out of a horse’s diet.

Chocolate

Chocolate contains theobromine and caffeine, two stimulants that can affect the heart and nervous system. Although horses are unlikely to seek out chocolate on their own, it should never be offered as a treat or reward.

Onions and Garlic

Onions and garlic contain sulfur compounds that can damage red blood cells through oxidative injury. While experimental studies have demonstrated Heinz body anemia in horses fed large amounts of garlic, veterinarians generally recommend avoiding both onions and garlic because they belong to the same Allium family and share similar toxic compounds.

Avocados

Avocados contain persin, a naturally occurring compound that can be toxic to several animal species. Although published evidence in horses is limited, veterinarians recommend avoiding the fruit, skin, leaves, and pit because their safety has not been established.

Coffee, Tea, and Other Caffeinated Products

Coffee, tea, energy drinks, and other products containing caffeine are not suitable for horses. Caffeine is a stimulant that can affect the cardiovascular and nervous systems, and these products should always be kept out of reach.

Alcohol

Alcoholic drinks, including beer, should never be given to horses. Alcohol affects the central nervous system and provides no nutritional or health benefit.

Foods That Can Cause Digestive Problems

Not every unsuitable food is poisonous. Some foods are unlikely to cause toxicity but may still upset a horse’s digestive system, particularly if eaten in large amounts or introduced suddenly. Because horses rely on a stable population of microbes in the hindgut to digest fiber, abrupt dietary changes or excessive treats can increase the risk of digestive upset.

Potatoes

Raw potatoes, green potatoes, sprouts, and potato plants should not be fed to horses. Green potatoes contain higher concentrations of glycoalkaloids, including solanine, which can be harmful if consumed. Even cooked potatoes offer little nutritional value for horses and are best avoided.

Potato leaves and stems contain even higher concentrations of glycoalkaloids than the tuber itself and should never be available to grazing horses.

Tomatoes

Ripe tomatoes are not considered highly toxic in small amounts, but green tomatoes, leaves, stems, and vines contain higher levels of glycoalkaloids. Because horses gain little nutritional benefit from tomatoes and safer treats are available, most veterinarians recommend avoiding the plant altogether.

A visual guide showing which foods horses should never eat, which foods are safe only in moderation, and which foods should be avoided in large amounts.

Cabbage, Broccoli, and Cauliflower

Cabbage, broccoli, and cauliflower are not considered toxic to horses and can be offered occasionally in small amounts. However, feeding large quantities may contribute to digestive upset or increased gas production, so moderation is important. If you’d like more detailed feeding guidance, including serving recommendations and preparation tips, see our guide on whether horses can eat cabbage, cauliflower, or broccoli.

Bread and Other Processed Foods

Bread, cakes, cookies, chips, and other processed human foods are not appropriate treats for horses. They are often high in starch, sugar, salt, or fat and provide little nutritional value. Regular feeding may increase the risk of digestive disturbances and contribute to obesity or metabolic disease.

Healthier Treat Alternatives for Horses

Not every fruit or vegetable needs to be avoided. Many can be offered occasionally as treats when fed in appropriate amounts alongside a balanced forage-based diet. Treats should never replace hay or pasture and are best introduced gradually to reduce the risk of digestive upset.

Apples

Apples are a popular treat for horses and are safe when fed in moderation. They should be cut into smaller pieces to reduce the risk of choking, especially in horses that eat quickly.

Carrots

Carrots can be offered as an occasional reward and are well accepted by most horses. Although nutritious, they contain natural sugars and should be fed in moderation, particularly to horses with equine metabolic syndrome or insulin dysregulation.

Bananas

Bananas, including the peel, can be fed in small amounts if the horse accepts them. Because they are relatively high in sugar, they should remain an occasional treat rather than a regular part of the diet.

Oranges

Most horses can safely eat peeled oranges in moderation. The fruit provides vitamin C and moisture, but its acidity means some horses may not enjoy the taste.

Grapes

Fresh grapes can be offered as an occasional treat for most healthy horses. While grapes are toxic to dogs, there is no evidence that they have the same effect in horses. Because grapes are high in natural sugars, they should be fed in moderation, especially to horses with obesity, insulin dysregulation, or equine metabolic syndrome.

Watermelon

Watermelon flesh is generally safe as an occasional treat. Remove the rind if your horse has difficulty chewing large pieces to help reduce the risk of choking.

Celery and Cucumbers

Celery and cucumbers are low-calorie treats that many horses enjoy. As with any new food, introduce them gradually and feed only small amounts. If you’re unsure about serving celery, see our complete guide on whether horses can eat celery.

What Should You Do If Your Horse Eats Something Unsafe?

Finding out your horse has eaten a potentially unsafe food can be worrying, but the best response depends on what was eaten, how much was consumed, when it happened, and whether your horse is showing any clinical signs. Some foods cause only mild digestive upset, while others require prompt veterinary attention even before symptoms develop. Not every accidental exposure becomes an emergency, but potentially toxic foods should always be taken seriously.

If you know or suspect your horse has eaten a food that should not be fed:

• Remove any remaining food to prevent further consumption.
• Estimate what was eaten and approximately how much.
• Monitor your horse for changes such as colic, diarrhea, reduced appetite, depression, or abnormal behavior.
• Contact your veterinarian promptly if the food is known to be toxic or your horse develops any concerning signs.

Because horses cannot vomit, owners should never attempt to make a horse “throw up” after eating something unsafe. Unlike many other species, horses are physically unable to vomit, which is one reason some toxic exposures require prompt veterinary assessment.