No, horses cannot eat tomatoes! Tomatoes are part of the nightshade family of foods, therefore we never recommend that you feed them to your horse for any reason. Similar to potatoes, tomatoes are toxic to horses because they contain small amounts of the poison solanine.
In general your horse should be fine if it has eaten some of the tomato fruit, as this contains relatively low amounts of solanine when compared to the “green parts” of the tomato plant. Under no circumstances should your horse be allowed to eat leaves from a tomato plant as they have the potential to be very upsetting for a horses stomach. In large enough quantities the tomato plant even has the ability to kill a horse!
To make matters worse with tomatoes the green leaves also contain the chemical atropine. This chemical has the effect of slowing down gut motility in horses. This is very dangerous for horses which are already very prone to developing colic.
Because of this you are going to want to ensure that you are never growing tomato plants anywhere near where you stable your horses or allow them to graze. Horses do not instinctively know what is good or bad for them, therefore your horse may very well eat tomato leaves without even giving it a second thought.
If you believe that your horse has ingested parts of a tomato plant then it is highly recommend that you contact your vet or your local animal poison control helpline. Remember, a small amount of any substance if unlikely to cause harm to your horse, but if you’re ever in doubt it is better to be safe than sorry. Never feed something to your horse that you’re not sure about, and always seek medical attention for your animal if you are worried!
Got any stories about your horse eating tomatoes? Let us know in the comments below!