Can Dogs Eat Tomatoes? Ripe Fruit vs Green Parts
A little ripe tomato is generally fine. Green tomatoes, stems and leaves are the problem.
Only with care
Dogs
Safe amount
A small piece of ripe, plain tomato now and then.
How to prepare it
Ripe red flesh only, plain and cut small. Remove the stem and leaves. Skip green tomatoes, and skip sauces, which often contain onion and garlic.
Risks
The ASPCA lists the tomato plant (leaves, stems and green fruit) as toxic to dogs because of solanine, and says the ripe fruit is non-toxic. Eating the green parts can cause stomach upset and, in larger amounts, more serious signs. Poisoning is rare. If your dog ate tomato plants or green tomatoes, call your vet.
Sources
This is not vet advice
If your pet has eaten something it should not have, call your vet or an animal poison hotline now. Do not wait for symptoms.