Can dogs eat tomatoes?
Updated 5 August 2026
Ripe red tomatoes are fine for dogs in small amounts, but this one earns its caution rating. Green tomatoes and every part of the plant contain tomatine, which can poison a dog, and most cooked tomato sauces carry onion and garlic. Stick to a slice of ripe tomato, nothing else.
The detail
The confusion here is fair: the tomato is a nightshade, and parts of it genuinely are toxic to dogs. The ripe red fruit is not one of those parts.
The Pet Poison Helpline explains that the plant's alkaloids, tomatine and solanine, sit in the green material: leaves, stems, vines and unripe fruit. As a tomato ripens and turns red those levels drop to a minimal amount, which is why a slice of ripe tomato is a safe share and a raid on the grow bag is not.
In a UK summer the real-world risk is the greenhouse or the patio grow bag, where a bored dog can eat leaves, vines and green fruit together. The kitchen risk is different: tomato rarely arrives alone, and the onion and garlic cooked into most sauces are toxic to dogs in their own right.
Risk by form
| Ripe red tomato | Fine in small amountsWash it and remove the green stalk |
| Green or unripe tomatoes | Toxic. Tomatine and solanine |
| Leaves, stems and vines | The most concentrated source of the alkaloidsKeep dogs out of the greenhouse |
| Pasta sauce, ketchup, tinned soup | Avoid. Onion, garlic, salt and sugar |
| Plain tinned tomatoes | Not dangerous, not worth servingCheck flavoured tins for garlic |
How much is sensible
| Dog size | Sensible amount |
|---|---|
| Small (under 10kg)Chihuahua, Jack Russell | Half a ripe cherry tomato, occasionally |
| Medium (10 to 25kg)Cocker spaniel, border collie | A slice of ripe tomato or one cherry tomato |
| Large (over 25kg)Labrador, German shepherd | A couple of slices or two cherry tomatoes |
| Dogs with sensitive stomachs | Skip it. The acidity sets some dogs off even when ripe |
Ripe red tomatoes
A fully ripe red tomato, washed and with the green stalk pulled off, is fine in small amounts. The flesh is mostly water and carries only around 3g of sugar per 100g.
Keep it occasional rather than routine. Tomato acidity gives some dogs a loose stool, and there is nothing in the fruit a complete dog food has missed.
Green tomatoes and the tomato plant
This is where the caution rating comes from. Unripe green tomatoes, leaves, stems and vines all carry tomatine and solanine, and the Pet Poison Helpline lists vomiting, diarrhoea, weakness, wobbliness and confusion among the signs of poisoning.
If you grow tomatoes, keep the dog out of the greenhouse and away from the grow bags, and clear windfalls before the garden patrol finds them. A dog that has chewed plants or eaten green fruit needs a vet call with a guess at the amount, not a wait-and-see.
Can dogs eat cherry tomatoes?
Ripe ones, yes, in ones and twos. The rules are the same as for large tomatoes, just in a format that rolls off the counter more readily.
Halve them for small dogs, since a whole cherry tomato is a plausible choking size for a Chihuahua-sized throat. Green cherry tomatoes off the vine count as unripe fruit and are not for sharing.
Cooked tomato and pasta sauce
The tomato in a cooked sauce is not the problem; the recipe is. Nearly every pasta sauce, tinned soup and pizza topping starts with onion and garlic, and Battersea describes the onion family as particularly toxic to dogs whether dry, raw or cooked.
Salt and sugar levels in jarred sauces are built for humans too. A lick of plain passata is harmless, and a bowl of leftover bolognese is a vet call for the onion, not the tomato.
Tinned tomatoes
Plain tinned tomatoes are ripe fruit and juice, so a stolen mouthful is nothing to panic about. Some brands add salt or citric acid, and flavoured tins often add garlic and herbs, which moves them onto the no list.
There is no reason to serve them on purpose. If a tin gets raided, check the label for garlic and onion before deciding whether it is a shrug or a phone call.
Signs to watch for
- Vomiting or diarrhoea after green tomatoes or plant material
- Weakness or unusual tiredness
- Wobbliness or confusion after larger amounts
If your dog overdoes it
A slice of ripe tomato needs no action. If your dog has eaten green tomatoes, leaves or vines, ring your vet with your dog's weight and a guess at the amount eaten. Do the same for any sauce containing onion or garlic. Out of hours, Vets Now runs emergency clinics across the UK.
Common questions
My dog ate a ripe tomato off the counter. Should I worry?
No. Ripe red tomato is the safe part of the plant, so the worst likely outcome is a loose stool from the acidity. Fresh water and carry on.
My dog ate tomato plant leaves. What do I do?
Ring your vet with your dog's weight and a guess at how much was eaten. The leaves carry tomatine, and the Pet Poison Helpline lists vomiting, weakness and wobbliness among the signs to expect.
Can dogs eat cherry tomatoes?
Ripe ones, yes, one or two at a time. Halve them for small dogs and never share green ones off the vine.
Can dogs have ketchup or pasta sauce?
No. Ketchup is salt and sugar with no upside, and most pasta sauces contain onion and garlic, which Battersea lists as particularly toxic to dogs. Leftover bolognese is a vet call, not a treat.
Are tinned tomatoes safe for dogs?
Plain ones are not dangerous, though the added salt in some brands makes them pointless as a share. Flavoured tins often contain garlic, so check the label if a tin gets raided.
Can puppies eat tomatoes?
Best to wait. A puppy gains nothing from tomato that its food lacks, and a puppy allowed to see tomatoes as food is harder to keep out of the vegetable patch later.
How many green tomatoes are dangerous?
There is no published safe number, and size, amount and the individual dog all change the picture. Treat any green tomato or plant ingestion as worth a phone call to your vet.