Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

What are the first signs of a cat eating green tomato plant and how long do they last?

Cats · Emergency guide

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Signs may appear within hours, lasting a few days. Watch for drooling, vomiting, diarrhea, and abdominal pain. If these occur, call your vet immediately. It's urgent as solanine can affect the nervous system.

Why is this dangerous?

These plants make solanine and tomatine, bitter alkaloids that irritate the gut and, in larger amounts, affect the nervous system. The plant concentrates them in leaves, stems, sprouts and green skin to deter animals from eating them.

Ripe red tomatoes and the white flesh of peeled potatoes contain only trace amounts, which is why they are considered safe in small food amounts.

Why speed matters

Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.

Signs to watch for

  • Drooling, vomiting, diarrhoea
  • Abdominal pain, loss of appetite
  • Lethargy, weakness, depression
  • Wobbliness, tremors, dilated pupils
  • Slow heart rate, collapse or seizures in large ingestions

What to do right now

  1. Call your vet or a poison line and say which part of the plant was eaten.
  2. Remove the pet from the vegetable patch and fence or net the plants.
  3. Do not induce vomiting unless instructed.
  4. Ripe tomato fruit and cooked plain potato in small amounts are not the concern — the green parts are.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

The step-by-step response, from the first minute to the vet visit, is in our Tomato & Potato Plants (Solanine) emergency guide.

Open the full emergency guide: Tomato & Potato Plants (Solanine) →