Valerian's root and rhizomes (underground stems) contain its active ingredients, including valepotriates and pungent odiferous oils.
Valerian is used as a sedative and sleep aid and is especially popular in Europe. In 2 relatively well-designed studies, valerian improved sleep quality and shortened the time needed to fall asleep. However, there is still insufficient clinical data to confirm whether valerian is effective for insomnia.
Some people take valerian for headaches, depression, irregular heartbeat, and trembling. There is not enough scientific evidence to determine whether valerian works for these conditions. It is usually used for short periods of time (4 to 6 wk), and studies suggest that it is generally safe to do so.
Valerian may prolong the effect of other sedatives (eg, barbiturates) and affect driving or other activities requiring alertness.
Last full review/revision May 2009 by Ara DerMarderosian, PhD
Content last modified October 2010