Is Oregano toxic to cats?
Oregano is mildly toxic to cats (S1 Caution): the ASPCA lists gastrointestinal irritants causing mild vomiting and diarrhea — an upset stomach, not a poisoning.
- TOXINgastrointestinal irritants
- WHAT TO EXPECTvomiting (mild); diarrhea (mild)
- CALL THE VETCall your vet if vomiting or diarrhea persists or worsens, or your cat stops eating or drinking.
Symptoms
| SIGN |
|---|
| vomiting (mild) |
| diarrhea (mild) |
If your cat just ate it
Care at a glance
FAQ
What happens if my cat eats oregano?
A mild stomach upset, on the ASPCA's record. The entry lists the toxic principle as "Gastrointestinal irritants" and the signs as "Mild vomiting and diarrhea" — nothing systemic, no contact irritation, and no amount specified. That is exactly the shape of an S1 Caution grade: the record stops at the gut, and the source itself calls it mild. Pet Poison Helpline has no oregano entry. Move the pot out of grazing reach and watch for vomiting or diarrhea; if either persists or worsens, or your cat stops eating or drinking, call your vet.
Is oregano oil covered by this verdict?
No — our record covers the plant, and the sources say nothing about the oil. The ASPCA's oregano entry is for Origanum vulgare hirtum, the growing herb, with "Gastrointestinal irritants" and "Mild vomiting and diarrhea" as its whole record; it does not mention essential oil, and Pet Poison Helpline has no oregano entry at all. We do not extend a plant grade to a concentrated extract, so the S1 Caution here applies to leaves and stems only. If a pet has swallowed oregano oil, that is a question for your vet or a poison hotline, not for this page.
Which herbs on the same windowsill are safe, and which are not?
On our records, most are safe and oregano is one of the exceptions. The ASPCA lists basil, rosemary, thyme, sage, cilantro, and lemon balm as non-toxic — all S0 Safe. Oregano is S1 Caution on "Mild vomiting and diarrhea," and garden mint is S1 too, with vomiting and diarrhea after large ingestions. Parsley is S2 Irritant for a skin reaction after large amounts. None of these is a poisoning; the S1 and S2 herbs are the ones to keep out of grazing reach. Every grade above links to its record.
Is oregano toxic to dogs?
Mildly. The ASPCA lists oregano as "Toxic to Dogs, Toxic to Cats, Toxic to Horses," with "Gastrointestinal irritants" as the toxic principle and "Mild vomiting and diarrhea" as the signs. Nothing beyond the stomach is on the record, which is why the grade is S1 Caution on our oregano page for dogs rather than S2. Dogs meet it in the herb bed more often than cats do. Move the plant out of reach and watch for vomiting or diarrhea; call your vet if it persists or your dog stops eating or drinking.