FrançaisCan dogs eat tomatoes? The short answer
Yes, a little ripe red tomato is generally considered safe: Pet Poison Helpline calls ripe tomatoes non-toxic, and the ASPCA states that the ripe fruit is non-toxic [1, 2]. The green parts are different. Leaves, stems and unripe green tomatoes contain more of the plant’s alkaloids, and large amounts may cause digestive and nervous signs [1].
If your dog has eaten the tomato plant or green tomatoes and drools, vomits, seems weak or stumbles, call your vet or a pet poison line now. Call too if it ate a sauce or dish made with onion or garlic, or a lot of salty food [7].
Why the green parts are the concern: tomatine
Tomatoes belong to the nightshade family (Solanaceae), like potatoes and eggplants. These plants make glycoalkaloids, natural compounds that protect them. The two main ones in tomatoes are α-tomatine and α-dehydrotomatine, and they are found in all parts of the plant [3]. The ASPCA lists the toxic principle of the tomato plant as solanine, the better-known alkaloid of potatoes [2]. In wild nightshades, the Merck Veterinary Manual places the glycoalkaloid in the leaves, shoots and unripe berries [4].
Levels vary a lot between plant parts. These are the α-tomatine contents measured in one analysis of the cultivated tomato plant, as reported by the European Food Safety Authority (EFSA) [3]:
| Part of the plant | α-tomatine (mg per kg, fresh) |
|---|---|
| Flowers | 1,100 [3] |
| Leaves | 975 [3] |
| Small stems | 896 [3] |
| Calyx (the green star on top of the fruit) | 795 [3] |
| Small immature green fruit | 465 [3] |
| Large immature green fruit | 144 [3] |
| Ripe red fruit (total glycoalkaloids, several surveys) | Averages of about 5 or less; often below the detection limit [3] |
Tomatine falls as the fruit grows and ripens. It gradually disappears as the red pigment lycopene appears, and late in ripening it is converted into other, related compounds [3, 6]. In one cultivar followed over 60 days, tomatine dropped below the measurable level once ripening began [3]. Call your vet or a pet poison line whatever the amount.
How these compounds cause harm: they bind to cholesterol-like molecules in cell membranes and damage them, which can irritate the lining of the gut. They also block acetylcholinesterase, an enzyme of the nervous system [3]. This fits the mix of digestive and nervous signs described below.
What the evidence actually shows in dogs
Real evidence in dogs is thin. In its 2020 review of glycoalkaloids in food and feed, which covered tomatoes, EFSA found no studies of their effects in dogs or cats, and no data on how tomato glycoalkaloids are absorbed in any species [3]. In our own search of the veterinary literature, we found no published case report of a dog poisoned by a tomato plant.
The closest published case involves a related plant. A 10-week-old Labrador puppy that ate creeping nightshade (Solanum dulcamara), including dried stems and unripe berries, became weak, wobbly and trembling, with depressed breathing and alertness and a mild fever. He vomited plant material, recovered with supportive care and went home; the authors described it as the first report of this plant poisoning a dog [3, 5]. How much alkaloid he took in was not measured [3].
In people, EFSA notes that there is no evidence that α-tomatine is a substance of concern and no reports of acute poisoning from eating green tomatoes [3]. A 2024 review still describes the glycoalkaloids of immature tomatoes as harmful in excess [6]. So the honest summary is: ripe fruit is low-risk, green parts deserve caution, and poisoning in dogs appears rare and poorly documented.
Signs to watch for after a dog eats the tomato plant
- Digestive signs: drooling, loss of appetite, vomiting and diarrhea; the ASPCA describes severe gastrointestinal upset [1, 2].
- Nervous signs: lethargy, weakness, stumbling and disorientation [1]; in the puppy that ate nightshade, tremors and depressed breathing [5].
- Eyes and heart: dilated pupils and a slow heart rate are listed by the ASPCA [2].
- Who is at risk: signs are described after large amounts of green tomatoes, leaves or stems [1]. A dog that digs in the vegetable garden or chews the vines is more exposed than one given a slice of ripe tomato.
None of the sources we reviewed gives a time course for these signs in dogs. If your dog shows any of them after access to tomato plants, call your vet whatever the amount.
Marinara, pizza and ketchup: what else is in the sauce
In sauces, the tomato itself is rarely the main problem. What is cooked with it matters more:
- Onion and garlic: common in marinara, pizza sauce and salsa. They irritate the gut and can damage red blood cells and cause anemia; cats are even more sensitive [7]. See onion and garlic toxicity in dogs.
- Salt: too much salt can cause marked thirst and urination and abnormal blood electrolytes, with vomiting, diarrhea, depression, tremors and seizures in severe cases [7]. Dogs that eat too much salt usually vomit within several hours [8].
- Tomatine in processed products: in one US market survey, stewed red tomatoes held 1.1 mg/kg of glycoalkaloids, ketchup 25 mg/kg, a red tomato sauce 57 mg/kg and pickled green tomato products 28 to 72 mg/kg [3]. These figures are contents, not doses known to harm dogs.
Keep the recipe or the label when you call: the vet will want to know about onion, garlic and salt. Call your vet or a pet poison line whatever the amount. Other kitchen foods with their own risks are covered in fruit pits and seeds and nuts and dogs.
What the vet checks, and what the tests show
None of the sources we reviewed describes a blood or urine test that measures tomato alkaloids in dogs. The vet relies on what the dog ate and on the exam, and treatment is supportive, as in the nightshade puppy [5]. Blood tests look for the effects of vomiting, salt or onion rather than for the tomato itself.
| Check | What it looks for | Why |
|---|---|---|
| Physical exam | Drooling, dilated pupils, slow heart rate, weakness, stumbling, tremors | These are the signs listed for the tomato plant and related nightshades [1, 2, 5] |
| Hydration and electrolytes (sodium, chloride, potassium) | Fluid losses after vomiting or diarrhea | Vomiting and diarrhea often cause dehydration with normal sodium; in one study of dogs and cats with high sodium, they were the most common cause [9] |
| Serum sodium | Salt poisoning, if the dog ate a salty sauce or food | A serum sodium above 160 mEq/L points to salt toxicosis; the vet then corrects water and sodium slowly [8] |
| Blood count with a smear | Damaged red blood cells and anemia, if the sauce held onion or garlic | Onion and garlic can damage red blood cells [7]; see the CBC for dogs |
Potassium and chloride lost through vomiting are explained in potassium in dogs and cats. All the foods to keep away, with the tests for each, are in toxic foods for dogs and cats.
Related articles
Other foods explained: avocado, grapes and raisins and chocolate.
En français : tomate et chien.
Questions to ask your veterinarian
- Was the amount of leaves, stems or green tomatoes my dog ate enough to worry about?
- Are my dog’s heart rate and pupils normal?
- After the vomiting, are hydration and electrolytes normal?
- The sauce contained onion or garlic: should we check the blood count?
- Could salt in the food explain the signs, and should sodium be measured?
Get your dog’s blood work explained together.
AI DiagAnimals reads the blood count, chemistry and electrolytes together with your laboratory’s intervals, and prepares the questions for your vet. The service opens soon: leave your email to be told first.
Frequently asked questions
Are tomatoes bad for dogs?
Ripe red tomatoes are considered non-toxic to dogs [1, 2]. The leaves, stems and green fruit contain more glycoalkaloids, and large amounts may cause vomiting, diarrhea, weakness and stumbling [1, 3].
Is marinara sauce safe for dogs?
It is not a good idea. The tomato is rarely the issue: marinara often contains onion and garlic, which can damage red blood cells, and salt, which in excess causes thirst, vomiting and tremors [7]. Call your vet if your dog ate a lot of it or seems unwell.
Can dogs eat cherry tomatoes?
The sources make no distinction by variety: ripe fruit is considered non-toxic, while green fruit, stems and the green calyx hold more alkaloids [1, 3]. Levels also vary between cultivars [3]. Offer only ripe fruit, without the green parts.
What happens if a dog eats a tomato plant?
Ripe fruit is considered non-toxic [1, 2]. Large amounts of leaves, stems or green tomatoes may cause drooling, vomiting, diarrhea, weakness, stumbling, dilated pupils or a slow heart rate [1, 2]. Call your vet or a pet poison line whatever the amount.
Are green tomatoes toxic to dogs?
They contain far more tomatine than ripe ones: up to about 465 mg/kg in small immature fruit in one analysis, against levels that are often undetectable once the fruit ripens [3]. Poisoning in dogs is rarely documented, but keep dogs away from green tomatoes and vines [1, 3].
Sources
- Pet Poison Helpline. Tomato. petpoisonhelpline.com/poison/tomato
- ASPCA Animal Poison Control Center. Toxic and non-toxic plants: Tomato plant. aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/tomato-plant
- EFSA Panel on Contaminants in the Food Chain (CONTAM), Schrenk D et al. Risk assessment of glycoalkaloids in feed and food, in particular in potatoes and potato-derived products. EFSA J. 2020;18(8):e06222. doi.org/10.2903/j.efsa.2020.6222
- Davis TZ. Range plants of temperate North America. Merck Veterinary Manual. Reviewed November 2023. merckvetmanual.com/toxicology/poisonous-plants/range-plants-of-temperate-north-america
- Kees M, Beckel N, Sharp C. Successful treatment of Solanum dulcamara intoxication in a Labrador retriever puppy. Can Vet J. 2015;56(12):1283-1286. pubmed.ncbi.nlm.nih.gov/26663926
- Wang LH et al. Review on toxicology and activity of tomato glycoalkaloids in immature tomatoes. Food Chem. 2024;447:138937. doi.org/10.1016/j.foodchem.2024.138937
- ASPCA Animal Poison Control Center. People foods to avoid feeding your pets. aspca.org/pet-care/aspca-poison-control/people-foods-avoid-feeding-your-pets
- Thompson LJ. Salt toxicosis in animals. Merck Veterinary Manual. Reviewed May 2022. merckvetmanual.com/toxicology/salt-toxicosis/salt-toxicosis-in-animals
- eClinPath, Cornell University College of Veterinary Medicine. Sodium. eclinpath.com/chemistry/electrolytes/sodium
Laboratory methods and reference intervals vary. This article explains; it does not diagnose. For a decision about your pet, use the original report and talk to your veterinarian. Our editorial policy.