1,3-Butanediol (also known as 1,3-butylene glycol, butane-1,3-diol, or 1,3-dihydroxybutane) is an organic chemical, an alcohol. It is commonly used as a solvent for food flavouring agents and is a co-monomer used in certain polyurethane and polyester resins. It is one of four stable structural isomers of butanediol. In biology, 1,3-butanediol is used as a hypoglycaemic agent. 1,3-Butanediol can be converted into β-hydroxybutyrate and serve as a substrate for brain metabolism.