Medically Reviewed by Melinda Ratini, MS, DO on May 17, 2023
2 min read

Passionflower is a vine that grows in warm areas of the southern U.S., Mexico, and South America. It's been used for centuries to try to treat sleep issues, boils, earaches, liver problems, and other ailments.

In the U.S. passionflower is available in a variety of forms, including:

  • Capsule
  • Extract
  • Dried
  • Oil

Passionflower has been used by some people to try to treat insomnia. But there is little evidence that it works. 

Today, supplements containing passionflower are often marketed as relaxation aids.

Passionflower is also taken by some people to try to relieve anxiety. Some small studies suggest that it may be helpful, though they are not conclusive.

One study suggests that passionflower may help people who are addicted to drugs such as heroin and morphine by lessening the anxiety they feel during withdrawal. But the researchers say their results need to be tested more before any conclusions can be drawn.

Another small study shows that passionflower may lessen anxiety among people about to undergo surgery.

Passionflower oils and extracts are sometimes applied to the body to try to treat hemorrhoids and burns. However, no studies have examined its effectiveness for such uses.

Passionflower extract is sometimes used to flavor foods. It is, according to the FDA, generally recognized as safe.

Several side effects have been reported, including:

Passionflower may interact with certain medications. For example, it may increase the effects of pentobarbital and benzodiazepine drugs. Both of these drugs are used to lessen anxiety and insomnia.

Passionflower may also interact with:

Passionflower should not be taken by pregnant women. That's because it may stimulate the uterus and potentially induce labor.

People expecting to undergo surgery should stop taking passionflower at least two weeks before the procedure. That's because passionflower may interact with anesthesia and other medication during and after surgery.

The FDA regulates supplements under a different set of regulations that it uses for "conventional" foods and drugs. If you take passionflower, be sure to tell your doctor. They can give you specifics about safety and drug interactions.