Bishop's Weed

Yes, Bishop's Weed (Ammi majus) is potentially toxic to cats. It contains furanocoumarins that can cause dermatitis, photosensitivity, drooling, and gastrointestinal upset whether your cat ingests it or simply brushes against it.

Watch for sunburn-like skin redness, blistering, or hair loss on lightly furred areas like the ears, nose, belly, and around the eyes — especially after a sunny day following contact with the plant. If your cat chewed the plant, drooling or mouth irritation is also possible.

Contact your veterinarian immediately if you suspect contact or ingestion. Call ASPCA Animal Poison Control at (888) 426-4435 for triage. Keep your cat indoors and out of sunlight, since the furanocoumarin reaction requires sun exposure to develop — signs may not appear until hours or even a day after contact.

Bishop's Weed causes photosensitization, meaning the furanocoumarins it contains react with UV light to damage skin tissue. Symptoms like redness, blistering, or sunburn-like patches typically don't appear until after the cat has been exposed to sunlight following contact — so reactions are often not seen until hours or up to a day later.

Yes, Bishop's Weed (Ammi majus) is potentially toxic to dogs. It contains furanocoumarins that can cause vomiting, lethargy, and — after sun exposure — painful skin blistering and photosensitization.

Chewing the plant can trigger intense mouth burning, drooling, vomiting, and difficulty swallowing within minutes. Over the following 24–72 hours, sun exposure may cause redness, swelling, blistering, or scabbing on lightly haired areas like the muzzle, ear tips, belly, and around the eyes. Some dogs also squint or show signs of eye irritation.

Keep your dog out of direct sunlight immediately — this is critical to preventing photosensitization skin lesions. Call your vet right away if your dog is drooling heavily, vomiting repeatedly, or refusing food, or if you notice any skin blistering or eye irritation in the days after exposure. You can also reach the ASPCA Animal Poison Control Center at (888) 426-4435.

Oral symptoms like drooling and vomiting appear within minutes of chewing. Skin lesions from photosensitization typically develop 1–3 days after ingestion once the dog is exposed to sunlight, and resolution can take days to weeks depending on the dose ingested and how much sun exposure occurred. Exact recovery timelines are not well documented for this plant.