Passionflower (Passiflora incarnata) was used traditionally in the Americas and later in Europe as a calming herb for anxiety, insomnia, seizures, and hysteria. It is still used today to treat anxiety and insomnia. Scientists believe passionflower works by increasing levels of a chemical called gamma aminobutyric acid (GABA) in the brain. GABA lowers the activity of some brain cells, making you feel more relaxed.
The effects of passionflower tend to be milder than other herbs used to treat anxiety including valerian (Valeriana officinalis) and kava (Piper methysticum). Passionflower is often combined with valerian, lemon balm (Melissa officinalis), or other calming herbs. Few scientific studies have tested passionflower as a treatment for anxiety or insomnia, however. Because passionflower is often combined with other calming herbs, it is difficult to tell what effects passionflower has on its own.
Studies of people with generalized anxiety disorder show that passionflower is as effective as the drug oxazepam (Serax) for treating symptoms. Passionflower didn't work as quickly as oxazepam (day 7 compared to day 4). However, it produced less impairment on job performance than oxazepam. Other studies show that patients who were given passionflower before surgery had less anxiety than those given a placebo, but they recovered from anesthesia just as quickly.
Native to southeastern parts of the Americas, passionflower is now grown throughout Europe. It is a perennial climbing vine with herbaceous shoots and a sturdy woody stem that grows to a length of nearly 10 meters (about 32 feet). Each flower has 5 white petals and 5 sepals that vary in color from magenta to blue. According to folklore, passionflower got its name because its corona resembles the crown of thorns worn by Jesus during the crucifixion. The passionflower's ripe fruit is an egg-shaped berry that may be yellow or purple. Some kinds of passionfruit are edible.
The above-ground parts (flowers, leaves, and stems) of the passionflower are used for medicinal purposes.
Available forms include the following:
No studies have examined the effects of passionflower in children, so DO NOT give passionflower to a child without a doctor's supervision. Adjust the recommended adult dose to account for the child's weight.
Speak to your doctor for specific recommendations for your condition.
The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.
DO NOT take passionflower if you are pregnant or breastfeeding.
For others, passionflower is generally considered to be safe and nontoxic in recommended doses and for less than 2 months at a time.
Passionflower may interact with the following medications:
Sedatives (drugs that cause sleepiness)
Because of its calming effect, passionflower may make the effects of sedative medications stronger. These medications include:
Antiplatelets and anticoagulants (blood thinners)
Passionflower may increase the amount of time blood needs to clot, so it could make the effects of blood-thinning medications stronger and increase your risk of bleeding. Blood-thinning drugs include:
Monoamine oxidase inhibitors (MAO inhibitors or MAOIs)
MAO inhibitors are an older class of antidepressants that are not often prescribed now. Theoretically, passionflower might increase the effects of MAOIs, as well as their side effects, which can be dangerous. These drugs include:
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Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.
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