Tiglic acid is a monocarboxylic unsaturated organic acid. It is found in croton oil and in several other natural products. It was also isolated from the defensive secretion of certain beetles. Tiglic acid has a double bond between the second and third carbons of the chain. Tiglic acid and angelic acid form a pair of cis-trans isomers. Tiglic acid is a volatile and crystallizable substance with a sweet, warm, spicy odour. It is used in making perfumes and flavoring agents. The salts and esters of tiglic acid are called tiglates. Tiglic acid is a skin and eye irritant. The inhalation of the substance causes respiratory tract irritation. It is listed on the Toxic Substances Control Act (TSCA).In 1819 Pelletier and Caventou isolated a peculiar volatile and crystallizable acid from the seeds of Schoenocaulon officinalis, a Mexican plant of family Melanthaceae (also called cevadilla or sabadilla). Consequently, the substance was named sabadillic or cevadic acid.