Herbs & Supplements:
Passionflower
Passiflora incarnata

Principal Proposed Uses
  • Anxiety, Chemical Dependency
Other Proposed Uses
  • Insomnia, Nervous Stomach

The passionflower vine is a native of the Western hemisphere, named for symbolic connections drawn between its appearance and the crucifixion of Jesus. Native North Americans used passionflower primarily as a mild sedative. It quickly caught on as a folk remedy in Europe and was thereafter adopted by professional herbalists as a sedative and digestive aid.

What Is Passionflower Used for Today?

In 1985, Germany's Commission E officially approved passionflower as a treatment for "nervous unrest." The herb is considered to be a mildly effective treatment for anxiety and insomnia, less potent than kava and valerian, but nonetheless useful. Like melissa (lemon balm), chamomile, and valerian, it is also used for nervous stomach. However, there is only weak supporting scientific evidence that passionflower works for these purposes.

Preliminary human trials suggest that passionflower might be helpful for anxiety⁹ and chemical dependency.¹⁰ Animal studies suggest that passionflower extracts can reduce agitation and prolong sleep.^1,11-13 

The active ingredient in passionflower is not known.

Dosage

The proper dosage of passionflower is 1 cup 3 times daily of a tea made by steeping 1 teaspoon of dried leaves for 10 to 15 minutes. Passionflower tinctures and powdered extracts should be taken according to the label instructions.

What Is the Scientific Evidence for Passionflower?

Anxiety

A 4-week double-blind study of 36 individuals with anxiety (specifically, generalized anxiety disorder) compared passionflower to the standard drug oxazepam.⁹ Oxazepam worked more quickly, but by the end of the four week trial, both treatments proved equally effective. Furthermore, passionflower showed a comparative advantage in terms of side-effects: use of oxazepam was associated with more job-related problems. However, because this study lacked a placebo group, it would be premature to conclude from it that passionflower has been shown to be an effective treatment for anxiety.

Chemical Dependency

A 14-day double-blind trial enrolled 65 men addicted to opiate drugs, and compared the effectiveness of passionflower combined with the drug clonidine vs. clonidine alone.¹⁰ Clonidine is a drug widely used to assist narcotic withdrawal. It effectively reduces physical symptoms such as increased blood pressure. However, clonidine does not help emotional symptoms such as drug craving, anxiety, irritability, agitation and depression. These symptoms can be quite severe and often cause enrollees in drug treatment progreams to end participation. In this 14 day study, the use of passionflower along with clonidine significantly eased the emotional aspects of withdrawal as compared to clonidine alone.

Safety Issues

Passionflower is on the FDA's GRAS (generally recognized as safe) list.

The alkaloids harman and harmaline found in passionflower have been found to act somewhat like the drugs known as MAO inhibitors and also to stimulate the uterus,^3,4 but whether whole passionflower has these effects remains unknown. Passionflower might increase the action of sedative medications.^5,6,7 Finally, there are five case reports from Norway of individuals becoming temporarily mentally impaired from a combination herbal product containing passionflower.⁸ It is not clear whether the other ingredients may have played a role.

Safety has not been established for pregnant or nursing mothers, very young children, or those with severe liver or kidney disease.

Interactions You Should Know About

If you are taking sedative medications, passionflower might exaggerate their effect.

Last reviewed March 2002 by Medical Review Board

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