Is a Tomato Poisonous? – Toxicity to Humans, Dogs, and Cats
Is a Tomato Poisonous? – The Short Answer
Ripe tomatoes are not poisonous. The red fruit you eat is safe for humans, dogs, cats, and horses. The green parts of the tomato plant - the leaves, stems, and unripe fruit - are mildly toxic to dogs, cats, and horses because of two compounds the plant produces: solanine and tomatine.
This distinction matters. If you are searching because a child ate something from a tomato plant, or a dog got into the garden, the answer depends entirely on what they ate. A ripe red tomato is not a poisoning. A mouthful of tomato leaves is a different situation, though rarely a serious one.
What Part of the Tomato Plant Is Toxic?
Two glycoalkaloids make the plant toxic: solanine and tomatine. Solanine is present throughout the foliage and in unripe green tomatoes. Tomatine concentrates in the green fruit. Both compounds are natural defenses the plant uses against insects and disease.
Concentrations are highest in the leaves and stems, lower in unripe green tomatoes. As the fruit ripens, both compounds break down. A fully red, ripe tomato contains only trace amounts that are harmless to humans and pets. Cooking does not reliably destroy solanine, so cooked green tomatoes or cooked leaves are not safe alternatives.
The tomato plant belongs to the Solanaceae family, also called nightshade, which includes deadly nightshade (belladonna). This family connection is the reason tomatoes spent centuries wrongly believed to be poisonous to humans.
Is the Tomato Plant Poisonous to Dogs and Cats?
Yes, the green parts are toxic to both dogs and cats. Horses are also susceptible. The ASPCA lists the tomato plant as toxic to all three. The Pet Poison Helpline rates the toxicity as mild in dogs and cats.
This matters for practical risk assessment. The ripe fruit is not a problem. A dog that steals a cherry tomato off the counter has not been poisoned. A dog that chews through a tomato plant in the garden has eaten something mildly toxic. Large amounts are needed for severe effects, and deaths are essentially unheard of.
If your pet has gotten into a tomato plant, the situation warrants a call to the vet or poison helpline but is not a medical emergency in most cases.
Symptoms of Tomato Plant Poisoning in Pets
Dogs and cats may show some or all of the following after eating green plant material: hypersalivation, vomiting, diarrhea, loss of appetite, lethargy, weakness, depression, dilated pupils, or a slow heart rate. Symptoms typically appear within a few hours of ingestion.
Horses may develop gastrointestinal signs including colic, along with lethargy and loss of appetite.
How much is dangerous? Smaller dogs and puppies are at higher risk because less plant material is needed to produce symptoms. Most pets recover fully with prompt veterinary care, and severe poisoning requires eating a substantial amount of plant material.
Can Humans Eat Tomatoes? What About Green Tomatoes?
Ripe red tomatoes are safe and are eaten by billions of people worldwide. They are not a health risk.
Green tomatoes and tomato leaves contain solanine. Eating a large amount can cause stomach upset, headache, or dizziness in humans, but serious poisoning is rare. There are no documented cases of human death from eating tomato plant parts.
The historical fear of tomatoes as poisonous to humans was based on their membership in the nightshade family. That fear was never well-founded for ripe fruit. If you grow tomatoes and have children who spend time in the garden, treat tomato plants the same way you treat any plant that is not food: supervise small children and teach them that the leaves and green fruit are not for eating.
Tomato Poisoning in Children
Children are at higher risk than adults because they may put plant material in their mouth out of curiosity. They are more likely than adults to eat tomato leaves or bite into an unripe green tomato.
Symptoms in children are the same as in adults: nausea, vomiting, diarrhea, and stomach pain. If your child has eaten any part of a tomato plant, contact poison control at 1-800-222-1222 or seek medical attention. Bring a photo or sample of the plant if you can.
What to Do If Someone Has Eaten a Tomato Plant
- Remove any remaining plant material from the mouth.
- Rinse the mouth with water.
- Do not induce vomiting unless a medical professional or poison control operator specifically directs you to.
- Call poison control for humans (1-800-222-1222) or the ASPCA animal poison helpline (888-426-4435) for pets. Have the plant photo or sample ready.
- If symptoms are severe or worsening, go to an urgent care clinic or emergency room.
- For pets, contact your veterinarian and follow their guidance.
Frequently Asked Questions
Are ripe tomatoes poisonous? Fully ripe (red) tomato fruit is considered safe for humans, dogs, cats, and horses. Unripe green tomatoes and all green parts of the plant contain solanine and can be mildly toxic, so unripe fruit should not be eaten in quantity, especially by pets. When in doubt, treat green or under-ripe tomatoes as unsafe.
Is tomato sauce or cooked tomato safe for pets? Cooked ripe tomatoes in plain food are generally safe in small amounts. Avoid tomato sauces that contain onions, garlic, salt, or seasonings, which are independently toxic to pets. Avoid any sauce made from unripe or green tomatoes.
Can dogs eat cherry tomatoes? Yes, if they are fully ripe and red. Do not feed green or unripe cherry tomatoes.
Are tomato plants poisonous to horses? Yes, the green parts are toxic to horses in the same way they are toxic to dogs and cats.
Can tomato plant toxicity kill a pet? Severe poisoning is extremely rare. Fatalities are essentially undocumented. Most pets recover fully with prompt veterinary care.
What does solanine do to the body? It irritates the gastrointestinal lining and can affect the nervous system at high doses. Effects are reversible with treatment, and serious harm is uncommon.