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Ragwort / Tansy
Senecio jacobaea or Tanacetum vulgare
Ragwort (Senecio jacobaea) and Tansy Ragwort are highly toxic plants for cats due to pyrrolizidine alkaloids (PAs) — compounds that cause severe, often irreversible liver damage. The toxicity is cumulative; even small repeated exposures cause progressive hepatic necrosis that may not become apparent until liver failure is advanced.
Important Notes
Toxic compounds: pyrrolizidine alkaloids (jacobine, senecioline, retrorsine); all parts toxic; hay containing ragwort retains toxicity when dried
Mechanism: PAs are metabolised to reactive pyrroles in the liver, forming DNA cross-links and destroying hepatocytes; damage is cumulative and irreversible
Symptoms: weight loss, lethargy, jaundice, neurological signs (head-pressing, blindness, circling); acute liver failure may occur with large single exposures
Dried ragwort in hay is a particular risk — it loses bitterness but retains full toxicity
Seek veterinary care promptly; early intervention before liver failure occurs greatly improves prognosis
Potentially Toxic Parts
Stem
Leaf
Flower
Seed
Possible Symptoms Reported in Cats
Liver damage
Hepatic · Not specified in the provided sources.
Disclaimer: This summary was compiled from multiple sources and is for informational use only. It is not a diagnosis or treatment plan. Toxicity can vary based on the substance, amount, plant part, and individual cat. If you think your cat may have been exposed to a toxic substance, contact a veterinarian right away.