Summary of best available evidence on the effectiveness of valerian for insomnia

Study	Sample (N)	Design	Intervention	Comparison	Outcome	Adverse events
Leathwood et al (1982)⁷	8	Crossover trial, 4 nights of each treatment in random order.	450 mg or 900 mg aqueous valerian extract.	Placebo	Valerian at both doses significantly reduced sleep latency and quality in early part of the night measured by movement wrist meters compared with placebo. (Effect size not reported in systematic review. No abstract available on Medline)	900 mg valerian resulted in greater sleepiness in the morning.
Leathwood & Chauffard (1985)⁸	128	Crossover trial, 3 nights of each treatment in random order.	400 mg aqueous valerian or combined 60 mg valerian/30 mg hops.	Placebo	Valerian improves sleep latency and quality compared with placebo. (Effect sizes not reported in systematic review. No abstract available on Medline.)	Nausea in 1 patient (group uncertain). Morning sleepiness greater in combined valerian/hops group.
Vorbach etal (1996)⁶	121	Multicentre, placebo controlled trial.	600 mg ethanol valerian extract (LI 156) for 28 days.	Placebo	4 validated rating scales. Valerian better than placebo on clinical global impression scale after 14 days. 66% rated valerian effective compared with 26% placebo.	2 patients on valerian reported headache and feeling dazed in the morning. Placebo effects not reported.
Donath et al (2000)³	16	Randomised, double blind, placebo controlled, crossover trial.	Radix valerianae (dose not reported in abstract).	Placebo	Polysomnographic (PSG) recordings. After multiple doses, slow wave sleep latency reduced with valerian v placebo (21.3 v 13.5 min, p<0.05) Slow wave percentage time also increased with valerian compared with placebo (9.8% v 8.1%, p<0.05). Subjective sleep quality correlated with these results.	Low adverse events in valerian group compared with placebo (3 v 18).
Ziegler et al (2002)²	202	Multicentre, randomised, double blind trial.	600 mg valerian LI 156 for 6 weeks	10 mg oxazepam	Similar effects on sleep quality and sleep questionnaire (refreshment after sleep, evening psychic stability, psychosomatic symptoms, dream recall, sleep duration).	28% valerian v 36% oxazepam. Mild only.