1,4-Butanediol 2,3-Butanediol 1,3-Butanediol is an organic compound with the formula CH3CH(OH)CH2CH2OH, not to be confused with 1,4 Butanediol.

With two alcohol functional groups, the molecule is classified as a diol.

[5] Hydrogenation of 3-hydroxybutanal gives 1,3-butanediol:[6] Dehydration of 1,3-butanediol gives 1,3-butadiene: 1,3-Butanediol has sedative, hypotensive and hypoglycaemic action comparable to ethanol, with the (R), also known as (D), enantiomer being more active.

[7][8] Fatty acid esters of 1,3-butanediol such as the acetoacetate, lactate or hexanoate have been researched for inducing ketogenesis.

[16] 1,3 Butanediol, | quote = Also referred to as 1,3-Butylene glycol, maintains FDA GRAS status as a flavor molecule.