A sedative, digestive bitter, and appetite stimulant, valerian is a tall, perennial plant that grows widely in North America, Europe, and Asia. Its root has long been used for medicinal purposes. The Greek physician Galen recommended valerian for insomnia in the second century A.D., and after falling out of common use for some time it became popular again from the sixteenth century on as a sedative, with wide usage in Europe and the United States. Until 1950, the U.S. National Formulary listed valerian as a sleep aid and antianxiety treatment. However, it fell out of favor once more, as U.S. medical doctors abandoned herbs as a form of treatment. Although valerian lost its place in American medicine after World War II, it continued to be used in Europe. Scientific studies on valerian in humans began in the 1980s, leading to its approval by Germany's Commission E in 1985. Germany's Commission E monograph lists valerian as useful for "restlessness and nervous disturbance of sleep." Today, valerian is available over the counter and is widely used as a remedy for insomnia in Germany, Belgium, France, Switzerland, and Italy. Valerian is considered generally somewhat more effective in treating insomnia than the herbs passionflower and hops but less effective than pharmaceutical sleeping pills such as the benzodiazepines.

Valerian contains many chemical constituents, including valepotriates, valerianic acid, valeric acid, and isovaleric acid. At one time, it was thought that the important chemical components of valerian were the valepotriates. Now we're not sure exactly which ingredients in valerian are most important. Currently, valerianic acid is being studied, but its role is still unclear.

Dosage
Valerian is typically taken in tincture, capsule, or tea form, 30 to 60 minutes before bedtime. To be an effective sedative, the tincture form should be taken in dosages of 1/2 to 2 teaspoons, depending on the concentration. The tea is made by pouring a cup of boiling water over 1 to 3gm of dried root and then leaving to steep for 10 to 15 minutes. Tablets, capsules, and dry extracts are usually taken at a dose of 150 to 600mg, depending on the formulation. When in doubt, follow the label instructions. As with any herb, a good guideline is to start with the smallest dosage first and increase only if needed.

Approved for use as a food, valerian is listed on the U.S. Food and Drug Administration's GRAS (generally regarded as safe) list. Although valerian does not appear to impair driving ability, it can diminish vigilance for a few hours after it's taken. Thus driving a car or operating hazardous machinery within a few hours of taking valerian is not recommended.

Aside from its strong odor - some find that valerian root smells unpleasantly like dirty socks - valerian is well tolerated, with only occasional mild gastrointestinal distress. With constant use, side effects can include headaches, excitability, digestive upsets, or sleep and heart disturbances. It is also possible for some people to develop a paradoxical effect from taking valerian, in which valerian actually gives them a mild stimulant effect rather than the expected sedating effect.

No drug interactions have been reported, but the possibility still exists that valerian might enhance other central nervous system depressants, such as sedatives, sleeping pills, and alcohol. Erring on the side of caution is recommended, by not combining valerian with any of these substances.

Warning: If you are on any prescription benzodiazepines, do not stop taking them without your physician's advice, as there can be severe consequences.

Safety in young children, pregnant or nursing women, and those with severe liver or kidney disease has not been established.