What it is
Native to the southern United States as well as Central and South America, passionflower is a fast-growing vine with showy purple and white flowers and sweet fruits. The flowers and leaves have a long history of use for easing anxiety and insomnia.

History and folk remedies
Spanish conquistadors introduced passionflower to Europe, after learning about the plant’s sedative effects from the Aztecs. In North America, early colonists found Native Americans using passionflower tea to calm anxiety. By the mid-1800s, passionflower was commonly used as a remedy for insomnia, restlessness, menstrual discomfort, and epilepsy, among other maladies.

Why it’s used
Today, herbalists continue the traditional use of passionflower as a sedative and mild tranquilizer. In Europe, many natural tranquilizers and sedatives include passionflower; because the herb is not addictive, it doesn’t require a prescription. Germany’s Commission E, an official herbal advisory board, lists passionflower as an approved treatment for “nervous unrest,” and the European Scientific Cooperative on Phytotherapy has approved passionflower for relieving tension, restlessness, irritability, and insomnia.

How it works
Although scientists have yet to determine exactly how passionflower works, research has shown that the herb contains a variety of tranquilizing compounds, including flavonoids. These compounds slightly sedate the central nervous system, which results in feelings of relaxation.

Scientific support
Animal studies have shown that passionflower has a sedating effect, and clinical studies of humans have shown the same to be true. In a four-week, double-blind study of 36 people suffering from anxiety disorder, passionflower was found to be as effective as the prescription drug Oxazepam in relieving anxiety symptoms. Although Oxazepam took effect more quickly, passionflower demonstrated equal effectiveness by the end of the trial. The researchers also noted that passionflower did not cause side effects, such as impairment of job performance, that are typical of Oxazepam (Journal of Clinical Pharmaceutical Therapy, 2001, vol. 26, no. 5).

Side effects
Passionflower is considered safe in the amounts generally recommended (see “How to Take It,” below). Pregnant women should not use medicinal amounts of passionflower because certain compounds in the herb (harmala alkaloids) act as uterine stimulants. Although the herb has not been associated with miscarriage, it would be wise for pregnant women to choose another soothing herb, such as chamomile. If you are taking prescription sedatives, check with your health care practitioner before taking passionflower because it may magnify the tranquilizing effects of the medication.

How to take it
Available as a bulk herb and included in some sleep and relaxation tea formulas, passionflower makes a pleasant-tasting tea. Pour 1 cup boiling water over 1 teaspoon of dried passionflower. Cover and steep for 10 to 15 minutes. Strain, sweeten if desired, and drink. For insomnia, drink 1 cup of tea 30 minutes before bed. For general anxiety and restlessness, drink up to 3 cups throughout the day. If you prefer, you can take passionflower as a concentrated liquid extract. Take 1/4 to 1 teaspoon at a time diluted in a small amount of warm water, up to three times a day.

An ounce of dried passionflower costs about $2; a 1-ounce bottle of liquid extract costs approximately $8.

Herbalist and author Laurel Vukovic lives in Ashland, Oregon, and has published nine books, including Herbal Healing Secrets for Women (Prentice Hall, 2000).