This issue of Veterinary Clinics: Food Animal Practice, guest edited by Dr. Steve Ensley and Dr. Tim Evans, focuses on Toxicology. Topics include: Hepatotoxic Plants that Poison Livestock; Plant-induced photosensitivity and dermatitis in livestock; Plant-induced reproductive disease, abortion and teratology in livestock; Myotoxic and cardiovascular toxic plants; Toxic plants that damage the gastrointestinal and urinary systems and miscellaneous toxic plants; Diagnostic guidelines for ruminant toxicosis; The use of blood/liver analysis to evaluate trace mineral status in ruminant livestock; Water quality for cattle; Biofuels coproducts tolerance and toxicology for ruminants; Ruminant mycotoxicosis; Commercial and industrial chemical hazards for ruminants; Safety of antibiotic drugs in food animals: comparison of findings from preapproval studies and postapproval experience in the United States with safety information in published literature; Treatment of animal toxicosis: a regulatory perspective, Selenium toxicosis; Sulfur toxicosis; Lichen toxicosis caused by Xanthoparmelia; Fescue/ergot toxicosis in ruminants; and Cu toxicosis in small ruminants and camelids.