Is Groundsel Toxic to Cats?
Also known as: Old-Man-In-The-Spring, Ragwort (common), Senecio vulgaris · Senecio vulgaris
What makes it toxic
Pyrrolizidine alkaloids (senecionine and relatives) in leaves, flowers and seeds. The liver converts them into compounds that kill liver cells — toxicity is cumulative rather than a one-bite crisis.
Warning signs to watch for
A single small meal may cause vomiting, diarrhea and lethargy. Chronic intake leads to weight loss, jaundice, photosensitivity and liver failure over weeks.
What to do if your cat eats it
Remove the weed and stop all access. Call your vet after a known ingestion and again about any repeated exposure — liver enzyme testing is sensible even before symptoms appear.
Common questions
Is one nibble of groundsel an emergency for a cat?
Usually not — expect mild stomach upset and watch closely. The documented danger is cumulative liver damage from repeated grazing, so prevent a second time.
Does drying the plant remove the alkaloids?
No — pyrrolizidine alkaloids persist in dried hay and clippings, which is how livestock are poisoned. Compost it away from pets.
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.