Can Dogs Eat Tomatoes? Ripe Is Fine, Green Is Not

By Marc Brannigan, Co-Founder & CEO

Ripe red tomato flesh is safe for dogs in moderation. Green tomatoes, and the stems, leaves and vines of the tomato plant, are not. This is one of the few foods on our list where the ripeness genuinely changes the answer, which is why so much of the advice online contradicts itself.

What solanine actually does

Tomatoes belong to the nightshade family, along with potatoes, aubergines and peppers. Green tomatoes and the green parts of the plant contain solanine and tomatine, glycoalkaloids the plant produces as a natural pesticide. As a tomato ripens, the solanine content falls away to negligible levels — which is precisely why ripe fruit is fine and unripe fruit is not.

At meaningful doses, solanine causes gastrointestinal upset, drooling, lethargy, dilated pupils, a slowed heart rate, confusion and muscle weakness. In practice, serious tomatine poisoning in dogs is uncommon, because a dog would need to eat a substantial quantity of green fruit or foliage. But "uncommon" is not "impossible", and garden dogs who chew vines are the realistic risk group.

If your dog has eaten green tomatoes or tomato plant material and is drooling, wobbly, vomiting repeatedly or unusually sleepy, call your vet. The ASPCA Animal Poison Control line is the other number worth having.

Is ripe tomato good for dogs?

Lycopene

Tomatoes are the single best dietary source of lycopene, the carotenoid antioxidant that gives them their colour. Interestingly, cooking increases lycopene availability rather than destroying it — though cooked tomato usually arrives with onion and garlic, which rules it out.

Vitamin C, potassium and folate

All present in useful amounts. As with other fruit, a dog on a complete diet already has these covered.

Fibre and water

Tomatoes are around 95% water with about 1.5 grams of fibre per medium fruit, which makes them low calorie — roughly 22 calories each.

Honest limitation

Tomato is a more acidic food than most fruit, and dogs with sensitive stomachs or a history of reflux often do not tolerate it well. It is not a food to push on a dog who is not keen.

How much tomato can a dog eat?

Dog size	Approximate weight	Ripe tomato per day
Toy	Under 10 lbs	1 small cherry tomato, quartered
Small	10 to 20 lbs	1 to 2 cherry tomatoes
Medium	20 to 50 lbs	A quarter of a medium tomato
Large	50 to 90 lbs	Half a medium tomato
Giant	Over 90 lbs	Up to one medium tomato

Tomato is an occasional treat rather than a daily one, both because of the acidity and because there is nothing in it a dog needs. Two or three times a week at most.

How to serve tomato safely

• Fully ripe only. Deep red, soft to the touch. If there is any green around the shoulders, cut it away or skip it.
• Remove the stem and the green calyx — the little star-shaped leafy part at the top. That is plant material, not fruit.
• Wash it. Tomatoes are commonly sprayed.
• Quarter cherry tomatoes. A whole cherry tomato is a near-perfect choking shape for a small dog.
• Plain and raw. No salt, no oil, no seasoning.

The tomato danger list

• Green or unripe tomatoes. Solanine. Covered above.
• Tomato plants — leaves, stems, vines. The highest concentration of glycoalkaloids on the whole plant. Fence the vegetable patch if your dog grazes.
• Tomato sauce, passata and pasta sauce. Almost always contain onion and garlic, both of which damage red blood cells in dogs. Our garlic guide covers the mechanism and the amounts involved. Also high in salt and often in sugar.
• Ketchup. Sugar, salt, vinegar, often onion powder. Not a dog food.
• Sun-dried tomatoes. Concentrated, usually salted, often packed in oil with garlic.
• Tomato soup. Cream, salt, onion. No.
• Tinned tomatoes. High in salt, and the acidity is more concentrated.

Why tomato is already in your dog's food

If you check the ingredient panel on a bag of dry food, you may well find tomato pomace listed. This surprises owners who have just read that tomatoes are risky, so it is worth explaining.

Tomato pomace is what remains after tomatoes are processed for juice and paste — the skins, pulp and seeds of ripe fruit. It is a legitimate, inexpensive source of soluble fibre, and it appears in plenty of reputable foods. It is made from ripe fruit, so the solanine question does not apply. Its presence is not a red flag, and it is not evidence that the manufacturer is padding the food out, though like any fibre source it should not be near the top of the ingredient list.

Which dogs should skip tomato

• Dogs with acid reflux or a sensitive stomach. The acidity is the problem. Skip it entirely.
• Dogs with a history of pancreatitis. The fruit itself is low fat, but tomato rarely arrives alone in a human meal. Keep the whole category away.
• Dogs with kidney disease. The potassium load matters. Ask your vet.
• Puppies. There is no good reason to give a puppy tomato. Skip it in favour of something gentler.

If you want a vegetable-style treat without the nightshade question

Tomato is one of the fiddlier fresh treats — ripeness matters, the green parts matter, and plenty of dogs simply do not tolerate the acidity. Carrot, cucumber and green beans do the same job with none of the caveats, and our guide to sharing human food safely covers more of them.

For something made for the purpose, our organic hemp dog treats come in a small-dog and a large-dog size, baked in Colorado with organic ingredients and full-spectrum hemp extract. One biscuit is one serving, with no ripeness to judge. The serving guide has amounts by weight.

Frequently asked questions

The bottom line

Fully ripe, washed, de-stemmed tomato flesh in small amounts is safe for most dogs and carries a genuinely good dose of lycopene. Green tomatoes and every green part of the plant should be kept well away, and every processed tomato product — sauce, ketchup, soup, sun-dried — is off limits because of the onion, garlic and salt that come with it. If your dog has a sensitive stomach, skip tomato altogether and give carrot instead.