Valerian, also known as all-heal and garden heliotrope, has been used as a medicinal treatment since ancient times, according to the National Center for Complementary and Alternative Medicine (NCCAM). It is used to treat anxiety, depression, headaches, heartbeat irregularity, sleep disorders and trembling.
Valerian hasn't been well-studied, so the possible side effects aren't well understood. There is little information regarding its interaction with other drugs and herbs, and no research has been done regarding the long-term effects of valerian.
Some people may be allergic to Valeriana officinalis. The Irritable Bowel Syndrome Treatment Center of Seattle, Wash., includes valerian on its allergy test panel.
Common Side Effects
Valerian has been reported to cause gastrointestinal upset. Dizziness, headaches and itchiness are other common side effects, according to the Office of Dietary Supplements (ODS). Medline Plus reports that excitability, uneasiness and unsteadiness are other commonly reported valerian side effects.
Valerian is used as an anti-anxiety and sleep aid but it may affect the ability to concentrate or operate machinery. Research concerning such effects is conflicting: one study found that valerian increased daytime sleepiness and another found that it didn't affect alertness, concentration or reaction time, according to ODS.
Some people don't gain sedative effects from valerian. Instead, they may become restless and sleepless, reports naturopath Beth Burch. Chronic and long-term use of valerian may result in insomnia, according to Medline Plus.
The ODS warns that valerian may increase drowsiness when combined with other sedatives or supplements.
Valerian side effects may include addiction similar to that which occurs with drugs, reports Medline Plus. Valerian withdrawal has been noted in chronic users: confusion, delirium and rapid heartbeat. Another side effect of valerian use is a drug "hangover," reports Medline Plus.
Heart and Liver
Valerian has the potential for negative side effects on the heart and liver, according to Aetna Intelihealth. Liver toxicity has occurred with the use of herbal preparations that contain valerian, reports Medline Plus. Also, valerian may interact with anti-seizure medications.