Butyric acid (from Greek Î²Î¿ÏÏ„Ï…ÏÎ¿, meaning butter), also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2–COOH. Saltsand esters of butyric acid are known as butyrates or butanoates. Butyric acid is found in butter, parmesan cheese, and vomit, and as a product of anaerobic fermentation (including in thecolon and as body odor). It has an unpleasant smell and acrid taste, with a sweetish aftertaste (similar to ether). It can be detected by mammals with good scent detection abilities (such as dogs) at 10 ppb, whereas humans can detect it in concentrations above 10 ppm.