Why?
Parsley contains furanocoumarins, compounds that in large amounts can cause photosensitization: the skin reacts to sunlight with redness or irritation. That's why it appears on some lists of plants toxic to cats. A nibbled sprig now and then is harmless, though it doesn't add anything special to your cat's diet.
How much?
One or two small chopped sprigs now and then, fresh and well washed, is plenty. Don't make it a habit, and never give parsley that's seasoned or mixed with garlic.
The risks
- Photosensitization: skin redness or irritation in the sun
- Stomach upset in large amounts
- Parsley mixed with garlic: toxic
- Mix-ups with poison hemlock when foraged
Your cat ate some: what now?
A few sprigs of parsley are no problem. If your cat ate a large amount, watch for vomiting, diarrhea and redness on thinly furred areas like the ears and nose over the next 48 hours and the following days, and call your vet if those signs appear.
Better options
For safe greens to chew, catnip or a pot of cat grass (wheat or oat sprouts) are perfect. Basil is also considered non-toxic to cats.
Common questions
Does parsley help with cat bad breath?
It's a common idea, but parsley won't fix a cat's bad breath, which usually comes from tartar or dental disease. Have your vet check their mouth instead.
Is parsley in cat food safe?
Yes, the small amounts of dried parsley found in some cat foods are not a concern. The risk comes from large amounts of the fresh plant.
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.