Propynoic acid is a terminal acetylenic compound that is a 3-carbon, straight-chain, monounsaturated fatty acid having one acetylenic bond. It has a role as a xenobiotic metabolite. It is an acetylenic fatty acid, a monounsaturated fatty acid, a short-chain fatty acid, a terminal acetylenic compound and an alpha,beta-unsaturated monocarboxylic acid. It is a conjugate acid of a propynoate.