GradedHealth

Passionflower

Last reviewed October 2026 · Based on 14 studies

Bottom line

Passionflower may modestly ease anxiety and improve sleep quality, based on a few small trials. A 2022 network meta-analysis did not find a significant effect on anxiety scores, and no pregnancy or liver-safety data were found.

What it helps with

  • Eases anxiety — Mixed results, evidence grade C (Limited). Small RCTs (36 and 60 people) with a positive result, plus a 2022 network meta-analysis that found no significant effect; downgraded for small sample and inconsistency.
  • Helps you sleep — Benefit, evidence grade C (Limited). Two small RCTs (41 and 110 people); benefit on sleep quality and total sleep time, but other objective sleep measures did not differ; downgraded for small sample and mixed results.

What it is

Passionflower (Passiflora incarnata) is a plant used in traditional herbal medicine for insomnia and anxiety in Europe and as a sedative tea in North America [1].

What the research says

A 2008 trial of 60 adults found that 500 mg of a branded passionflower extract taken before surgery lowered anxiety scores more than placebo, without sedation [2]. A pilot trial of 36 adults with generalised anxiety found a passionflower extract did about as well as oxazepam over four weeks [3]. A 2022 network meta-analysis of 29 trials found passionflower did not significantly reduce anxiety scores overall [4]. A 2018 systematic review of single-herb trials rated passionflower among the most-studied herbs, with benefits comparable to standard anxiolytics, but called for larger trials [5]. For sleep, a trial of 110 adults with insomnia found total sleep time rose more than with placebo over two weeks (P = 0.049), while sleep efficiency and waking after sleep onset did not differ [6]. A trial of 41 healthy adults found better self-rated sleep quality after passionflower tea than after placebo tea [7].

Doses used in studies

Doses are from trials, not recommendations. Trials used 500 mg of a branded extract 90 minutes before surgery [2], 45 drops a day of a liquid extract for four weeks [3], and a cup of tea for one week per treatment period [7]. The dose in the 110-person insomnia trial is not given in its abstract [6].

Safety and interactions

Side effects: no adverse effects were observed across nine trials [8]. A questionnaire study of herb users reported skin reactions after passionflower, though it did not measure dose or cause [9]. Medicine interactions: a case report describes dizziness, shaking and muscle fatigue when passionflower and valerian were taken with the sedative lorazepam, and the authors suspect additive effects on the brain's GABA system [10]. Upper limits and toxic doses: no data found. Pregnancy and breastfeeding: no data found. Liver injury: no data found. Blood thinners, antidepressants, diabetes and blood-pressure medicines, and immune-suppressing drugs: no data found. Kidney disease and bleeding disorders: no data found. Quality: a review found many trials had weak methods and unclear extract strength [1].

Caveats and open questions

Most trials are small and short, from a single dose to four weeks [2][3][6]. The 2022 network meta-analysis did not confirm a significant anxiety effect [4]. A four-herb product that included passionflower lowered anxiety scores in healthy adults, but this does not show passionflower alone works [11]. A registered trial of passionflower for anxiety before dental extraction (72 people) is listed as completed; no published results were found.

References

  1. Passiflora incarnata L.: ethnopharmacology, clinical application, safety and evaluation of clinical trials.. J Ethnopharmacol, 2013.
  2. Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study.. Anesth Analg, 2008.
  3. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam.. J Clin Pharm Ther, 2001.
  4. Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis.. Pharmacol Res, 2022.
  5. Herbal medicine for depression and anxiety: A systematic review with assessment of potential psycho-oncologic relevance.. Phytother Res, 2018.
  6. Effects of Passiflora incarnata Linnaeus on polysomnographic sleep parameters in subjects with insomnia disorder: a double-blind randomized placebo-controlled study.. Int Clin Psychopharmacol, 2020.
  7. A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality.. Phytother Res, 2011.
  8. Passiflora incarnata in Neuropsychiatric Disorders-A Systematic Review.. Nutrients, 2020.
  9. Safety implications regarding use of phytomedicines.. Eur J Clin Pharmacol, 2006.
  10. Interactions of Valeriana officinalis L. and Passiflora incarnata L. in a patient treated with lorazepam.. Phytother Res, 2009.
  11. The chronic effects of a combination of herbal extracts (Euphytose®) on psychological mood state and response to a laboratory stressor: A randomised, placebo-controlled, double blind study in healthy humans.. J Psychopharmacol, 2022.