Are Tomato Plant Leaves and Stems Toxic to Pets?

Green parts vs. ripe fruit

The ASPCA identifies the toxic principle in tomato plants as solanine, concentrated in the green foliage and stems. It states plainly that the ripe fruit is non-toxic, so a ripe red tomato that a dog steals off the counter is not a poisoning concern (though whole cherry tomatoes can be a choking hazard for small pets).

The risk is the plant itself and unripe green tomatoes, which is worth remembering if pets have access to a vegetable bed or greenhouse where they might chew leaves, stems, or immature fruit.

Signs of eating tomato foliage

The ASPCA lists clinical signs including hypersalivation, inappetence (loss of appetite), severe gastrointestinal upset, depression, weakness, dilated pupils, and slow heart rate. In practice, a small nibble of a leaf tends to cause only mild, short-lived upset.

Larger ingestions are where the more serious signs become relevant, so the amount eaten matters. A pet that has eaten a lot of foliage and shows weakness, a slow heart rate, or dilated pupils needs prompt veterinary attention.

What to do and how to reduce risk

If your dog or cat eats a significant quantity of tomato plant leaves, stems, or unripe fruit, contact your veterinarian or the ASPCA Animal Poison Control Center at (888-426-4435). Note the amount and whether it was foliage or green fruit.

Fencing or otherwise keeping pets out of the tomato patch is the simplest safeguard, especially for animals that like to chew plants. For confirming the safety of any garden plant, see our page on how to check whether a plant is pet-safe.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• ASPCA - Toxic and Non-Toxic Plants: Tomato Plant (Lycopersicon spp.) — Lists the tomato plant (Lycopersicon spp.) as toxic to dogs, cats, and horses, toxic principle solanine in green foliage and stems, notes ripe fruit is non-toxic, and lists signs of hypersalivation, inappetence, severe gastrointestinal upset, depression, weakness, dilated pupils, and slow heart rate.

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