Can Dogs Eat Tomatoes? Ripe vs Green Explained

Ripe red tomato flesh is generally safe for dogs in small amounts. The green parts of the plant (stems, leaves, vines and unripe green fruit) contain tomatine and solanine and should be avoided. Tomato sauces, soups, ketchup and salsa often contain onion, garlic, salt or sugar, so skip them.

Tomatoes sit in a gray zone: the ripe fruit is mostly fine, but the plant it grows on isn't. That's why the answer depends on ripeness, form and where your dog found the tomato. A dog that snacks on a few ripe cherry tomatoes in the garden is very different from one that has chewed a whole plant. Check other foods in our food safety checker.

Ripe vs green tomatoes

Tomatoes belong to the nightshade family, along with potatoes and peppers. They contain glycoalkaloids (tomatine and solanine) that protect the plant from pests.

• Ripe red tomatoes: much lower in tomatine and solanine, because levels fall as the fruit ripens. A few small pieces are unlikely to cause problems for most dogs.
• Green tomatoes: higher in tomatine, which can irritate the gut and, in larger amounts, affect the nervous system and heart.
• Leaves, stems and vines: the highest concentrations. These are the real risk.

The amounts in a normal snack are small, and serious poisoning is uncommon. But dogs that raid a vegetable garden can eat a lot of plant material, so it's worth knowing the signs.

Signs of tomato plant poisoning

Signs can begin within hours of eating green tomatoes or the plant:

• Drooling
• Vomiting and diarrhea
• Belly pain
• Lethargy and weakness
• Confusion or unsteadiness
• Slow or irregular heartbeat
• Dilated pupils and tremors in severe cases

If your dog has eaten leaves, stems or many green tomatoes, call your vet or poison control rather than waiting for signs.

Are tomatoes good for dogs?

A ripe tomato is about 94% water and has roughly 18 kcal per 100 g. It supplies small amounts of vitamin C, potassium, vitamin K and lycopene. Dogs don't need any of these from tomatoes, so this is a treat rather than a nutrition strategy. The acidity can bother some stomachs, and some dogs simply don't like the texture.

How much tomato can a dog eat?

Because the fruit is so low in calories, the limit isn't the 10% treat rule but stomach comfort and the risk of eating green parts. Keep portions small and remove every bit of green.

Cut cherry and grape tomatoes in halves or quarters, since a whole one can be a choking risk for small dogs.

Worked example

Meet Hank, a neutered 20 kg (44 lb) dog.

1. RER: 70 × 20^0.75 = 70 × 9.46 = about 662 kcal.
2. Daily calories at 1.6 × RER: about 1,060 kcal.
3. Treat allowance at 10%: about 106 kcal.
4. Three cherry tomatoes (about 17 g each, 51 g total): 51 × 0.18 = about 9 kcal.
5. Result: under 10% of his treat allowance. Calories are trivial, so the question is digestion and making sure no stem or green tomato slipped in.

Plan your own dog's treat allowance with the dog calorie calculator.

Tomato products: what to avoid

• Tomato sauce, pasta sauce and pizza sauce: frequently contain onion, garlic, salt, sugar and oil. Onion and garlic are toxic to dogs.
• Ketchup: sugar, salt and often onion powder, sometimes artificial sweeteners.
• Tomato soup: salt, cream and seasoning.
• Salsa: onion, garlic, peppers and spices.
• Sun-dried tomatoes: very high in salt and concentrated.
• Canned tomatoes: plain, unsalted canned tomatoes with no added onion or garlic are less risky, but still acidic; keep portions tiny.
• Tomato-based dishes such as curry, chili and stew. Check every ingredient.

If your dog ate a product containing onion or garlic, contact your vet, because these can damage red blood cells.

Growing tomatoes with a dog at home

• Fence off the plants or use raised beds.
• Pick ripe fruit promptly so dogs can't grab fruit from low vines.
• Never compost green tomatoes or trimmings where dogs can reach them.
• Supervise dogs in the garden during the growing season.

Who should be careful?

• Dogs with acid reflux, frequent vomiting or a sensitive stomach: tomato acidity may make things worse.
• Dogs with kidney disease: ask your vet about potassium.
• Dogs with a history of pancreatitis: stick to the vet's plan.
• Puppies: a single small piece is plenty, given complete puppy food is the diet.

When to call your vet

Call your vet or poison control if your dog ate tomato leaves, stems, vines or lots of green fruit, or if you see drooling, repeated vomiting, diarrhea, weakness, tremors or a slow or irregular heartbeat. Also call if your dog ate a sauce or soup with onion or garlic. ASPCA Animal Poison Control Center: 888-426-4435. Pet Poison Helpline: 855-764-7661.