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Other common name(s): valerian, all-heal, garden heliotrope, valerian tea, valerian root, valerian extract

Scientific/medical name(s): Valeriana officinalis


Valerian is a flowering plant native to Europe, Asia, and the Americas. In herbal remedies, the plant's root and rhizomes (underground stems) are chopped and made into a tea or extract to be used primarily as a sedative. Although the fresh root has little odor, the dried root has an odor that is often described as being similar to dirty socks.


Valerian is an herb used for anxiety and sleeplessness. Although some research suggests that it is effective, the results have been inconsistent and, in many cases, the study methods have been flawed. More research is needed to make definite conclusions about its effectiveness. There are some side effects linked with long-term valerian use, and it has the potential to interfere with anesthesia and other medicines.

How is it promoted for use?

Herbal practitioners claim that valerian root or extract can lessen anxiety and nervous tension, promote sleep, help people quit smoking, ease congestion, and relieve muscle spasms. Generally, no one claims that valerian is useful for treating or preventing cancer.

What does it involve?

Valerian root is on the Commission E (Germany's regulatory agency for herbs) list of approved herbs. Supplements are available in tablets, capsules, liquid extracts or tinctures, and it can also be brewed as a tea. When taken as a sleep aid, the usual dosage of valerian extract in tablet form is 300 to 900 milligrams to be taken an hour or two before bedtime. For stress and anxiety, the usual dose is 50 to 100 milligrams taken 2 to 3 times a day, although some recommend doses of 200 milligrams or even 400 milligrams.

What is the history behind it?

For thousands of years, the Chinese, Greeks, Romans, and Indians have used valerian as a mild sedative. The origin of the word "pew" is said to come from the foul odor of the valerian root, which a first century AD Roman physician, Dioscorides, called phu. In the mid-1800s in the United States, the Shakers began growing valerian and other herbs to market to doctors and pharmacists in America and Europe. At that time, valerian was considered a stimulant. Valerian is sometimes used to flavor foods and drinks such as root beer.

What is the evidence?

Several controlled human studies have been conducted comparing valerian with a placebo. Some studies showed that those who took valerian had less insomnia and better sleep quality, while other studies showed no difference between valerian and placebo.

A German study compared valerian extract to oxazepam (a prescription anti-anxiety drug) in 202 adults over a 6-week period. The people taking valerian reported equal improvement in sleep quality, feeling rested, and how long they slept as those taking the prescription drug.

A randomized clinical trial in nearly 400 people compared valerian with kava or placebo. In 2005, it reported neither valerian nor kava was significantly better than placebo in reducing anxiety or improving sleep.

A number of other studies have found that valerian shortens the time it takes to fall asleep, although most of the studies had small sample sizes and short follow-up periods. Still other studies showed no effect. Of note, these studies used valerian from more than one source and used different doses, making results difficult to interpret.

Of interest, studies that have looked at only a single dose of the herb have tended to show no improvement in sleep at all. Longer studies suggested that improvement increased over a period of 2 to 4 weeks, suggesting that the herb may be more likely to work if taken over a period of a few weeks.

On the basis of animal studies and several clinical trials in Europe, German health officials have approved valerian as a sleep aid and mild sedative. While some experts trust in valerian's safety and effectiveness as a mild sedative, others are uncertain because of conflicting evidence. More research is needed to be sure of valerian’s effectiveness for sleep.

A 2007 Norwegian clinical trial of 405 patients with insomnia suggested that valerian might be slightly better than placebo and concluded that “…valerian appears to be safe, but with modest beneficial effects at most on insomnia compared to placebo.”

A 2011 study with more than 200 cancer patients from the Mayo Clinic gave 450 mg of valerian each night to one group and placebo (sham treatment) to the other group for a total of 8 weeks. The researchers found no significant benefit in measures of sleep, but people taking valerian reported less trouble with sleep. There was also some improvement in fatigue among those taking valerian compared to placebo. This effect calls for further study.

A 2006 evidence review of valerian and anxiety found only one study that used reliable research methods, and concluded that there is not enough evidence to know whether valerian might be useful as a treatment for anxiety disorders.

Another review in 2010 noted that most of the reported improvement in sleep that was attributed to valerian was not based on objective outcomes or quantitative measurements (such as observing how long people took to fall asleep when on the herb versus placebo). Additional research looking at these outcomes would be helpful.

Are there any possible problems or complications?

This product is sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must be tested before being sold), the companies that make supplements are not required to prove to the Food and Drug Administration that their supplements are safe or effective, as long as they don't claim the supplements can prevent, treat, or cure any specific disease.

Some such products may not contain the amount of the herb or substance that is on the label, and some may include other substances (contaminants). In a 2013 study, a test of 44 samples found that fewer than half the herbal supplements tested contained any of the herb that was listed on the label. More than half the samples contained ingredients that were not on the label. This suggests that the 2007 FDA rules to assure the proper listing of supplement ingredients are not always followed. Even when they are, the rules do not address the safety of the ingredients or their effects on health.

Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements, or if they even contain the ingredients on their labels. Although some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

A few supplement makers pay the US Pharmacopeia to test and verify that their products contain the ingredients listed on their label. These supplements all have the USP Dietary Supplement Verified mark on their labels.

Valerian is considered to be relatively safe when used in recommended doses over a few weeks. However, some people may notice restlessness and heart palpitations, especially with long-term use of valerian. Long-term or excessive use is not advised because of possible side effects, which include headaches, blurred vision, heart palpitations, itching, and nausea. A few people become excitable and unable to sleep when they take valerian. Rarely, liver damage has been linked to valerian, although it is uncertain whether valerian, contaminants, or other herbs caused the damage. Those who take valerian should tell their doctors so that their liver function can be monitored. Allergic reactions may also be possible..

Valerian should not be taken with alcohol, antihistamines, muscle relaxants, sedatives, anti-seizure drugs, narcotics, or any drugs used in treatment of mental illnesses because it might worsen drowsiness. People on cancer treatment medicines, anti-fungal drugs, allergy drugs, or medicines for high cholesterol should talk with their doctors or pharmacists about possible drug interactions before taking valerian. Because valerian may interact with anesthetics, people who are going to have surgery should not use valerian. However, suddenly stopping the herb has caused withdrawal symptoms in some people, so the dose of valerian should be tapered slowly, starting a few weeks before surgery. Always tell your doctor and pharmacist about any herbs you are taking.

People with liver or kidney disease should talk to their doctors before taking valerian. In very high doses, the herb may weaken the heartbeat and cause paralysis. Women who are pregnant or breastfeeding should not take valerian, and it shouldn’t be given to children younger than 3 years old.

Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

To learn more

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer


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Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 06/04/2014
Last Revised: 01/16/2015