Is St John’s Wort Toxic to Cats?
Also known as: Hypericum perforatum, Klamath Weed, Goatweed · Hypericum perforatum
What makes it toxic
Hypericin and hyperforin. Hypericin causes photosensitization — sun-exposed skin becomes inflamed — and the plant also irritates the gut.
Warning signs to watch for
Vomiting, diarrhea and drooling within hours; after sun exposure in light-skinned areas, redness, itching and crusty lesions can follow.
What to do if your cat eats it
Remove plant material, offer water and keep the cat out of direct sun for several days after ingestion. Call your vet if GI signs persist or skin lesions develop.
Common questions
Can St John’s wort supplements hurt my cat?
Yes — beyond plant toxicity, hypericin interacts with many medications. Never give your own mood or sleep supplements to a cat.
Why did my white cat get scabby after eating this plant?
Photosensitization fits that picture. Hypericin circulates in the skin and sunlight triggers inflammation on unpigmented areas — a vet visit is warranted.
More plants checked for cats
This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate something concerning, contact your veterinarian or a pet poison hotline right away. Checking what your pet can eat? Visit our sister site SafeOrToxic.