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Ingredient guide

Is passionflower safe? Side effects and who should avoid it

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Passionflower may be safe for short-term use. NCCIH says the tea may be safe for up to 7 nights and daily extract for up to 8 weeks, with possible drowsiness, dizziness and confusion. It should not be used in pregnancy, and it might add to the effects of anesthesia, so tell your surgical team.1

Key facts

  • No liver injury linked to passionflower is recorded in LiverTox.2
  • A review of nine trials found no memory loss or drop in test performance with passionflower.3
  • One published case describes a serious reaction at usual doses that needed hospital monitoring.4
  • In a European analysis, five of the six passionflower food supplements tested did not pass checks of identity and strength.5

Side effects reported

Possible side effects include drowsiness, dizziness and confusion.1

In a dental surgery trial, half of the people given passionflower reported sleepiness, against 82.5% of those given the sedative midazolam.3

Beyond sleepiness, the review of nine trials, lasting from one day to 30 days, found no adverse effects such as memory loss or a drop in test performance. The 30-day trial of 600 mg of extract at bedtime reported no adverse effects.3,6

In one published case, a woman developed severe nausea, vomiting, drowsiness and an abnormal heart rhythm after taking passionflower at usual doses, and needed hospital monitoring.4

Pregnancy and breastfeeding

Do not use passionflower if you are pregnant. NCCIH says it should not be used during pregnancy because it may induce uterine contractions and possibly lead to other problems. Little is known about whether it is safe while breastfeeding, so ask your doctor first.1

Surgery and medicines

Taken around the time of surgery, passionflower might slow the nervous system too much when combined with anesthesia or other medicines used before and after surgery. NCCIH advises talking to your health care provider if you take it within 2 weeks of a scheduled surgery.1

Apart from anesthesia and the medicines used around surgery, no official source we could find names a specific medicine that interacts with passionflower. Because it can cause drowsiness, ask before combining it with sedatives, sleep medicines or anything else that makes you sleepy.1

Taking it every day

No upper limit has been set for passionflower. NCCIH says the tea may be safe for up to 7 nights, and daily use of the extract may be safe for up to 8 weeks.1

NCCIH gives no safety estimate beyond 8 weeks of daily use, and whether passionflower is safe to put on the skin is not known. If you want to take it for longer, ask your doctor.1

Product quality

In a 2025 analysis of products sold in Europe, five of six passionflower food supplements failed identity or content tests, while all five registered herbal medicines passed.5

One of the failing products contained a single marker compound and none of passionflower's other typical compounds. A label alone cannot tell you what a capsule holds.5

Liver

LiverTox, NIH's database of liver injury from medicines and supplements, says passionflower has not been linked to raised liver enzymes or to liver injury.2

NCCIH says passionflower is likely safe when used as a flavoring in food.1

What's in ours

What’s in ours

  • Sleep: Passion Flower Extract, 100 mg per serving, from the label

Questions people ask

Is passionflower safe to take daily?

For up to 8 weeks, NCCIH says daily extract may be safe. There is not enough information on longer daily use, so ask your doctor before continuing past that.1

Can I drive after taking passionflower?

It can cause drowsiness, dizziness and confusion. Do not drive or use machinery until you know how it affects you.1

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Sources

  1. National Center for Complementary and Integrative Health. Passionflower. Bethesda (MD): National Institutes of Health. Last updated April 2025. Opened 2026-10-07.
  2. Passionflower. In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012 onward. Updated March 28, 2020. Summary read through PubMed. Opened 2026-10-07.
  3. Janda K, Wojtkowska K, Jakubczyk K, Antoniewicz J, Skonieczna-Żydecka K. Passiflora incarnata in Neuropsychiatric Disorders: A Systematic Review. Nutrients. 2020;12(12):3894. Opened 2026-10-07.
  4. Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol. 2000;38(1):63-66. Opened 2026-10-07.
  5. Brouns A, Lechtenberg M, Hensel A. Passionflower (Passiflora incarnata): Quality of Food Supplements Versus Registered Herbal Medicinal Products. Planta Med. 2025;91(9):532-540. Opened 2026-10-07.
  6. Harit MK, Mundhe N, Tamoli S, et al. Randomized, Double-Blind, Placebo-Controlled, Clinical Study of Passiflora incarnata in Participants With Stress and Sleep Problems. Cureus. 2024;16(3):e56530. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.