ChEBI: 4-hydroxybutyric acid is a 4-hydroxy monocarboxylic acid that is butyric acid in which one of the hydrogens at position 4 is replaced by a hydroxy group. It has a role as a general anaesthetic, a GHB receptor agonist, a sedative and a neurotoxin. It is a 4-hydroxy monocarboxylic acid and a hydroxybutyric acid. It is functionally related to a butyric acid. It is a conjugate base of a 4-hydroxybutyrate.