Paracetamol is extremely toxic to cats, which lack the necessary UGT1A6 enzyme to detoxify it. Initial symptoms include vomiting, salivation, and discoloration of the tongue and gums. Unlike an overdose in humans, liver damage is rarely the cause of death; instead, methemoglobin formation and the production of Heinz bodies in red blood cells inhibit oxygen transport by the blood, causing asphyxiation (methemoglobinemia and hemolytic anemia).

• Allen AL (June 2003). “The diagnosis of acetaminophen toxicosis in a cat”. The Canadian Veterinary Journal. 44 (6): 509–10. PMC 340185. PMID 12839249

Treatment of the toxicosis with N-acetylcysteine is recommended.

• Richardson JA (2000). “Management of acetaminophen and ibuprofen toxicoses in dogs and cats” (PDF). Journal of Veterinary Emergency and Critical Care. 10 (4): 285–91. doi:10.1111/j.1476-4431.2000.tb00013.x. Archived from the original (PDF) on 1 April 2010.