Abstract: Melamine is a kind of organic chemical material; however, rich in nitrogen, it has been added in food and feeds, which causes serious harm to the health of human and animals. Melamine has very low acute toxicity, and the lethal median dose (LD₅₀) is 3 100~3 300 mg · kg^-1. The symptoms for animals in chronic toxicity test include occurrence of kidney stone and carcinoma of urinary bladder. Melamine does not metabolize and transform in animal′s body, but excretes in the forms of protomer or homolog. The paper reviews the toxicity, residue metabolism and detection methods of melamine.