Yellow: with caution
Better not. Penn State Extension advises against giving horses tomatoes because they are a member of the nightshade family. The actual poison is mainly in the green parts.
Why the traffic light is yellow
The CliniTox database at the University of Zurich classifies the tomato as slightly toxic. The ripe fruit is considered non-toxic there. At the time of flowering, the herb contains 0.2 to 1.2 percent solanum alkaloids, especially tomatine, green fruits around 0.03 percent. According to CliniTox, large quantities of unripe tomatoes irritate the mucous membrane of the stomach and intestines.
The ASPCA also lists the tomato plant as poisonous to horses and cites salivation, loss of appetite, severe gastrointestinal complaints, fatigue, weakness, dilated pupils and a slow heartbeat. She calls the ripe fruit non-toxic.
Then why not green? According to EQUUS, a horse is practically unable to vomit, and gastrointestinal problems in horses quickly end up as colic. Because tomatoes are of no use and the line between ripe and unripe is blurred in everyday life, we advise against them.
What you should pay attention to
- Secure the vegetable garden: Tomato plants, leaves and green fruits belong out of reach, even over the fence.
- Garden waste: Do not throw uprooted tomato plants on or next to the pasture in autumn.
- No leftover food: Tomato sauce, salad and pizza do not belong in the food bucket.
- Better treats: According to Penn State, for example, cucumbers or carrots in small pieces are suitable.
What to do if your horse has eaten tomatoes?
A single ripe tomato is not an emergency. Nevertheless, observe your horse: does it eat normally, does it defecate, does it seem lively? If it has eaten large amounts of tomato plants or green fruits, call the vet's office. Drooling, weakness, diarrhea or signs of colic are reasons to call immediately.
If there are signs of poisoning, blocked throat or colic, call the veterinarian or the veterinary emergency service immediately.
Frequently asked questions
Are ripe tomatoes toxic to horses? According to CliniTox and the ASPCA, the ripe fruit is non-toxic. However, the plant and green fruits contain solanum alkaloids.
Are horses allowed to eat tomato leaves? No. According to CliniTox, the herb contains 0.2 to 1.2 percent alkaloids at flowering time and is the most poisonous part.
Read more
- Can horses eat potatoes?
- Can horses eat cucumbers?
- Horse weight calculator: How heavy is your horse?
- Buying a horse: the checklist
Quellen, abgerufen am 05.11.2026: CliniTox, Universität Zürich, Pflanzengifte: Lycopersicon esculentum; ASPCA, Toxic and Non-toxic Plants: Tomato Plant; Penn State Extension, Trick or Treat? Things to Think About When Giving Your Horse a Treat (Danielle Smarsh, Andrea Kocher); EQUUS, Q&A: Why can't horses vomit?
