Why?
Basil is listed as non-toxic to cats by veterinary references, and many cats enjoy nibbling it. It has no particular nutritional value for a carnivore, and eating a lot can simply upset the stomach. Preparations are the problem: pesto contains garlic, cheese and oil, and basil essential oil is far too concentrated for a cat.
How much?
One or two fresh, washed leaves now and then. If your cat nibbles your plant, that's fine within reason, as long as it wasn't treated with pesticides.
The risks
- Mild stomach upset if a lot is eaten
- Pesto: toxic garlic, plus cheese and oil
- Basil essential oil: too concentrated
- Pesticides on store-bought plants
Your cat ate some: what now?
A few basil leaves are no problem at all. If your cat ate a lot of the plant, watch for vomiting or diarrhea for 24 to 48 hours; if they ate pesto, call your vet because of the garlic.
Better options
Catnip and cat grass are made to be chewed too. If you want a basil plant your cat can nibble, choose an untreated one.
Common questions
Is basil safe for cats to chew on?
Yes, basil is non-toxic to cats, so chewing a few leaves of the plant is fine. Just make sure it hasn't been sprayed with pesticides.
Can cats eat pesto?
No. Pesto contains garlic, which damages a cat's red blood cells, plus cheese and lots of oil. Basil on its own is fine; pesto isn't.
This information is general and does not replace advice from a veterinarian. If your cat has swallowed something toxic, call your vet or an animal poison control center right away, without waiting for symptoms.