Valerian has been used as a medicinal herb since at least the time of ancient Greece and Rome. Hippocrates described its properties, and Galen later prescribed it as a remedy for insomnia. In medieval Sweden, it was sometimes placed in the wedding clothes of the groom to ward off the "envy" of the elves.^[1] Valerian can also be consumed as a kind of tea.

Because of valerian's historical use as a sedative, anticonvulsant, migraine treatment and pain reliever, most basic science research has been directed at the interaction of valerian constituents with the GABA neurotransmitter receptor system. These studies remain inconclusive and all require independent replication. The mechanism of action of valerian in general, and as a mild sedative in particular, remains unknown. Valerian extracts appear to have some affinity for the GABA_A receptor, a class of receptors on which benzodiazepines are known to act.^[11][12]

Valerian also contains isovaltrate, which has been shown to be an inverse agonist for adenosine A₁ receptor sites.^[13] This action likely does not contribute to the herb's sedative effects, which would be expected from an agonist, rather than an inverse agonist, at this particular binding site. Hydrophilic extractions of the herb commonly sold over-the-counter, however, probably do not contain significant amounts of isovaltrate (according to the paper cited previously).

Valerian is used for insomnia and other disorders as an alternative to benzodiazepine drugs, and as a sedative for nervous tension, hysteria, excitability, stress and intestinal colic or cramps.Valerian is also used for sleeping disorders, restlessness and anxiety, and as a muscle relaxant.It is sometimes recommended as a first-line treatment when risk-benefit analysis dictates. Valerian is often indicated as transition medication when discontinuing benzodiazepines.