Valerian is the common name given to the genus Valeriana, an odiferous, herbaceous perennial plant widely distributed in the temperate regions of Asia, Europe, and North America. It is among the most widely used herbal medicines in the world. Numerous clinical studies have demonstrated valerian's ability to improve sleep; however, to the best of our knowledge, no study has systematically assessed subjective and psychomotor/cognitive effects of valerian in young healthy adults across a range of doses. In the present study, we sought to determine whether valerian extract (Valeriana officinalis) altered mood and/or impaired psychomotor/cognitive performance in young healthy volunteers. We examined the effects of valerian extract (600, 1200, and 1800 mg) and 10 mg diazepam (positive control) compared to placebo in 10 young healthy volunteers. Dependent measures included subjective and psychomotor variables. The valerian extract had no significant effects on any of the dependent measures. Diazepam, though, produced subjective effects as measured by four different rating scales, and impaired psychomotor/cognitive performance. The data suggest that acute administration of valerian does not have mood-altering or psychomotor/cognitive effects in young healthy volunteers.