Although commercially sold valeriana tea products may contain a range of different herbs, the primary ingredient is usually valerian. The valerian plant (Valeriana officinalis) grows in North and South America but is native to Europe and China. The plant is famous for its distinct smell that many describe as similar to dirty socks.
Valeriana is traditionally used to relieve nervousness (calmative/sedative) and as a sleep aid. Valeriana is used as an hypnotic for insomnia and as an anxiolytic for restlessness and sleeping disorders associated with anxiety.
Valeriana contains a substance known as valerenic acid that is believed to affect gamma-aminobutyric acid receptors in the brain. It is believed that one of the purposes of valeriana is to control fear or anxiety experienced when nerve cells are overexcited. By doing so, valerian may act as a mild sedative and anxiolytic (anxiety-reducing drug).