Diazepam, commonly known by its brand name Valium, is a medication belonging to the benzodiazepine class of drugs. It is widely used for its anxiolytic, sedative, muscle relaxant, and anticonvulsant properties. Diazepam works by enhancing the effect of a neurotransmitter called gamma-aminobutyric acid (GABA) in the brain, which helps to produce a calming effect on the nervous system.