Cats
Potentially toxicConsulted references classify the plant as toxic or irritating for that pet type.
Verified against ASPCA/provenance audit 2026-05-06 on May 6, 2026.
Sources
cat safety reference
Is St. John's Wort safe for cats?
Hypericum perforatum
Klamath Weed is a perennial flowering plant known for its bright yellow blooms and medicinal history, but it contains compounds that can cause significant health issues if ingested by pets. It is widely recognized as a toxic plant that requires careful management in households with animals.
Common Saint John's WortGoatweedHypericum perforatumSt. John's Wort
- Light
- Full sun to partial shade
- Habit
- Upright, spreading perennial
- Care
- Low
Safety status
What this means for your cat
Cats: skin and sun matter more than the stomach here. ASPCA identifies hypericin as the toxic principle, and the characteristic injury is photosensitization — sun-exposed skin can develop ulcerative, weeping dermatitis after ingestion or contact.
What to watch for
ASPCA reports photosensitization presenting as ulcerative and exudative dermatitis — open, oozing sores especially on the nose, ear margins, and eyelids of cats with light or thin fur.
Time window
Specific onset and recovery durations are not documented in the ASPCA listing.
When to call the vet
Call any time you see ulceration, weeping skin lesions, or rapidly worsening irritation following suspected exposure. Open sores require veterinary attention to prevent secondary infection.
Sources: ASPCA (no first-aid guidance).
If a pet has chewed or swallowed plant material and is showing symptoms, contact a veterinarian or poison resource immediately. This product is for structured reference, not diagnosis.
Cats — concern notes
Common signs
Photosensitivity, skin irritation, drooling, vomiting, and potential neurological changes.
Escalation note
Ingestion can lead to severe skin reactions when exposed to sunlight. Please contact your veterinarian immediately if you suspect your cat has consumed any part of this plant.
Safer alternatives
No hand-picked alternatives for this plant yet. You can still pick your own using the Compare button on any other plant.
Source evidence
ASPCA Toxic Plant List
toxicology · 99% reliability
St. John's Wort is listed as toxic to both cats and dogs due to the presence of hypericin.
Questions about St. John's Wort
Is St. John's Wort toxic to cats?
Yes, St. John's Wort (Hypericum perforatum) is potentially toxic to cats. It contains compounds that can cause photosensitivity, skin irritation, drooling, vomiting, and potential neurological changes if ingested.
What symptoms does St. John's Wort cause in cats?
The most distinctive danger is photosensitization: cats that ingest St. John's Wort and are then exposed to sunlight can develop ulcerative and exudative dermatitis — open, oozing sores especially on the nose, ear margins, and eyelids. Cats with light or thin fur are particularly vulnerable. Other symptoms include drooling and vomiting.
What should I do if my cat ate St. John's Wort?
Contact your veterinarian immediately and call the ASPCA Animal Poison Control Center at (888) 426-4435. Keep your cat indoors and out of sunlight to reduce the risk of photosensitization reactions while you seek guidance, since sun exposure after ingestion can trigger severe skin lesions.
When do St. John's Wort skin lesions in cats require emergency vet care?
Call your vet any time you see ulceration, weeping skin lesions, or rapidly worsening irritation following suspected exposure. Open, oozing sores — especially around the nose, ear margins, or eyelids — require prompt veterinary attention to prevent secondary infection.
Same cat verdict
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