Gamma-Hydroxybutyric acid (4-hydroxybutanoic acid, C4H8O3) is both a drug and a naturally occurring substance found in the central nervous system where it might act as a neurotransmitter, as well as in other organs such as the liver, kidneys, heart and bones. GHB is structurally related to the ketone body beta-hydroxybutyrate. As a drug it is used most commonly in the form of a salt like sodium gamma-hydroxybutyrate (Na-GHB, sodium oxybate) or potassium gamma-hydroxybutyrate (K-GHB). The drug is often represented as a date rape drug, much in the same way as alcohol and rohypnol. It is often referred to as liquid ecstasy despite its unrelated effects.

Endogenous
Cells produce GHB by reduction of succinic semialdehyde. People with the disorder known as succinic semialdehyde dehydrogenase deficiency, also known as gamma-hydroxybutyric aciduria, have elevated levels of GHB in their urine, blood plasma and cerebrospinal fluid.[1]
The precise function of GHB in the body is not clear. It is an immediate precursor to GABA, a neurotransmitter which regulates awakeness, physical activity and sleep. As GABA cannot cross the blood-brain barrier, GHB obtained from food may be used for converting to GABA. GHB protects cells from oxygen starvation, which might explain presence of the compound in vital organs. GHB was also found to have neuroprotective capabilities.

Medical
It has been used as a general anesthetic, and a hypnotic in the treatment of insomnia. GHB has also been used to treat clinical depression and to improve athletic performance. In the United States, the Food and Drug Administration permits the use of GHB under the trade name Xyrem to reduce the number of cataplexy attacks in patients with narcolepsy. In Italy, under the trade name Alcover (ATC code N07BB), GHB is used in the treatment of alcoholism (50 to 100 milligrams per kilogram per day, in 3 or more divided doses), both for acute alcohol withdrawal and medium to long term detoxification. An author/scientist by the name of Gian Luigi Gessa has been researching alcoholism and the effects of various drugs to persons afflicted with said disease for the past ten years. His studies in 1998 note that GHB, as a pharmaceutical aid, can be much less toxic and much more effective than the leading pharmaceutical compound (disulfiram).

Recreational

Gamma-hydroxybutyrate powderGHB is an intoxicant. It has many street names, including G, Juice, Fantasy, Liquid Ecstasy, and Gamma-OH.

The sodium salt of GHB has a thin, very salty, chemical taste. At low doses, GHB can cause a state of euphoria, increased libido[2], increased sociality and intoxication. This kind of use is particularly common at rave parties. At higher doses, GHB may induce nausea, dizziness, drowsiness, agitation, visual disturbances, depressed breathing, amnesia and unconsciousness. The effects of GHB can last from 1.5 to 3 hours.

Some chemicals convert to GHB in the stomach and blood. GBL, or gamma-butyrolactone, is one such precursor. The dose of GHB is difficult to judge when in liquid form because the concentration of GHB may not be known.

Other precursors include 1,4-butanediol. There may be additional toxicity concerns with these precursors.