Valerian root is a common herb found in dietary supplements sold in the United States. It is also sold as herbs and tincture for teas, in capsule form and in dried root extracts. It is commonly used as an adjunct in the treatment of insomnia, as well as an anxiolytic to treat anxiety disorders. Because of these effects, valerian root has been studied as a potential treatment for hypertension. As always, it is imperative to consult with a health professional before attempting to self-medicate any condition with valerian root.

It is not clear what specific component of valerian root works to produce its effect, but the National Institutes of Health's Office of Dietary Supplements suggests that its medicinal properties come from the interaction of its various components rather than from a single compound within the root. Valerian root has a long history as a therapeutic agent, dating as far back as ancient Greece and Rome, when it was used to treat insomnia. Valerian root is studied as a treatment agent for conditions as varied as irritable bowel syndrome, gastrointestinal spasms and attention deficit disorder, but there is no conclusive evidence of its usefulness in those conditions.

Valerian root is sold in the United States as a dietary supplement, not as a drug or medicine, so the consistency and quality of various herbal preparations is not regulated or uniform. According to the University of Maryland Medical Center, scientists believe that valerian root increases the concentration of GABA in the brain. GABA is a neurotransmitter, a molecule the cells in the brain and nervous system use to communicate with each other. GABA helps regulate neurons and has a calming effect on the nervous system. Because of its calming effect, valerian has the effect of lowering the blood pressure, in particular if this is related to stress.

Not many studies address the question of using valerian root in the treatment of high blood pressure, or hypertension. A study cited by the "American Family Physician" journal in a 2003 article notes decreases in blood pressure in subjects taking valerian root for its effect on stress and anxiety. This indicates that taking valerian root for stress may decrease blood pressure, which is one of the effects stress and anxiety has on the body. Consult your doctor as to the appropriateness of only using valerian root to treat hypertension.

According to the University of Maryland Medical Center, valerian root is relatively safe, although pregnant and nursing mothers should avoid taking any valerian root supplements or products, since its effects on a fetus and babies are not well known. Some people who take valerian root exhibit a paradoxical reaction to the herb, with symptoms of anxiety and restlessness. Valerian root may increase the effects of sedatives and alcohol, so care should be taken when ingesting valerian root in combination with these agents.