Passionflower owes its name to Spanish missionaries, who saw symbols of the Passion of Christ in its flower. Behind this poetic name, what evidence supports the benefits of passionflower? Its traditional use is recognised in Europe, but only for herbal medicines, and clinical trials remain scarce. This article reviews the plant concerned, what the European Medicines Agency recognises, what studies show about stress and sleep, and the precautions to observe.
Key takeaways
- The passionflower used in herbal medicine is Passiflora incarnata, whose dried aerial parts are used.
- The European Medicines Agency recognises traditional use as a herbal medicine for mild symptoms of stress and as a sleep aid.
- Trials are few, small and short: findings are encouraging for anxiety before a procedure, but weaker for sleep.
- Drowsiness is possible: take care when driving and with sedatives; use is not recommended during pregnancy, breastfeeding or in children under 12.
Which passionflower are we talking about?
The genus Passiflora includes many species. The one used in herbal medicine is Passiflora incarnata, a vine native to the south-eastern United States and Central and South America. It should not be confused with Passiflora edulis, which produces passion fruit, or the blue passionflower grown in gardens, Passiflora caerulea.
The dried aerial parts are used: stems and leaves, sometimes with flowers and fruits, as an infusion, powder or extract. Encountered by Spanish explorers in the 16th century, the plant was subsequently introduced to Europe, where it entered folk medicine as a calming remedy.
What are its main constituents?
Passionflower mainly contains flavonoids, principally derivatives of apigenin and luteolin (isovitexin, isoorientin, schaftoside, swertisin and others). The European Pharmacopoeia requires at least 1.5% total flavonoids, expressed as vitexin, in the dried plant. It also contains maltol, a cyanogenic compound (gynocardin) and sometimes traces of alkaloids such as harman, which are undetectable in most commercial products.
Its mechanism of action is still debated. In rat brain preparations, a passionflower extract inhibits the reuptake of GABA, the nervous system's main inhibitory chemical messenger, and interacts with its receptors. These are laboratory findings and are not sufficient to predict an effect in humans.
What does the European Medicines Agency recognise?
In 2014, the European Medicines Agency's Committee on Herbal Medicinal Products (EMA) adopted a monograph on the aerial parts of Passiflora incarnata. It recognises the plant as a traditional herbal medicinal product for the relief of mild symptoms of mental stress and to aid sleep. This recognition rests exclusively on longstanding use, rather than conclusive clinical trials.
The monograph provides guidance for these medicines: 1 to 2 g of the plant infused in 150 ml of boiling water, one to four times daily, or 0.5 to 2 g of powder. It advises against use in children under 12, during pregnancy and breastfeeding, notes a possible effect on driving ability, and recommends seeking advice if symptoms persist for more than two weeks. Its periodic review began in 2025.
This framework applies to medicines. For food supplements, no health claim is authorised for passionflower: a manufacturer cannot attribute an effect on stress or sleep to it.
What do trials show about the benefits of passionflower?
Anxiety before a procedure
This is the best-studied situation. In 60 patients undergoing outpatient surgery, 500mg of passionflower taken 90 minutes before the procedure reduced measured anxiety compared with placebo, without increasing sedation. In 60 patients before spinal anaesthesia, an extract limited the rise in anxiety, with a significant but small difference. During wisdom tooth extractions in 40 volunteers, 260mg of passionflower provided anxiety control comparable to 15mg of midazolam, a benzodiazepine sedative, with less memory loss; this trial had no placebo group.
Generalised anxiety
A pilot trial in 36 patients with generalised anxiety disorder compared 45 drops of passionflower extract daily with 30mg of oxazepam, a benzodiazepine, over four weeks. No significant difference emerged; oxazepam acted faster but interfered more with work activities. Without a placebo group and with so few patients, this finding remains preliminary. The Cochrane review on this topic included only two trials (198 participants) and considers the evidence too limited to draw a conclusion.
Sleep
In 41 young adults, a cup of tea prepared with 2 g of the plant each evening for one week improved perceived sleep quality by 5.2% compared with a placebo tea. The other five sleep diary measures and laboratory recordings did not change. In 110 adults with insomnia, an extract taken for two weeks increased total sleep time measured in the laboratory by about 23 minutes, compared with no increase under placebo; other parameters did not differ from placebo.
| Situation studied | Participants | Dose and duration | Result |
|---|---|---|---|
| Outpatient surgery (2008) | 60 patients | 500mg, 90 min beforehand | Lower anxiety |
| Spinal anaesthesia (2012) | 60 patients | Extract, 30 min beforehand | Small difference |
| Wisdom teeth (2017) | 40 volunteers | 260mg, single dose | Similar to midazolam, no placebo |
| Generalised anxiety (2001) | 36 patients | 45 drops/day, 4 weeks | Similar to oxazepam, no placebo |
| Sleep quality (2011) | 41 adults | 2 g infusion, 7 days | Perceived quality +5.2% |
| Insomnia (2020) | 110 adults | Extract, 2 weeks | Sleep +23 min |
Why is the evidence still limited?
A 2020 systematic review identified nine clinical trials lasting from one to 30 days. Most reported reduced anxiety, less clearly in people with low anxiety, without notable adverse effects. However, these trials are small, use very different preparations (tea, drops, tablets, extracts) and sometimes compare passionflower with a medicine without a placebo group.
Several common claims also rely on animal studies, such as improved memory in rats or an antidepressant effect when combined with St John's wort in experimental models. These cannot be presented as proven benefits in humans.
What adverse effects and precautions should you know about?
The European monograph mentions no known adverse effects, but the US National Center for Complementary and Integrative Health (NCCIH) lists drowsiness, dizziness and confusion. It considers that passionflower may be safe as a tea for up to seven nights and advises against it during pregnancy because it may cause uterine contractions.
Regarding interactions, the EMA reports none, but the NCCIH notes that combining it with anaesthesia or medicines used around surgery could slow the nervous system too much. As a precaution, avoid combining it with other sedatives, sleeping tablets or alcohol, and mention its use before any procedure.
In what forms is passionflower available?
It is available as tea, tincture and capsules containing powder or extract, often combined with other plants or nutrients. Hexagon®'s Zen complex, for example, combines it with magnesium bisglycinate, L-tryptophan, taurine and vitamin B6. In this formula, only magnesium and vitamin B6 have authorised health claims; passionflower, L-tryptophan and taurine have none.
To understand these other ingredients, see our articles on forms of magnesium, vitamin B6 and taurine.
Frequently asked questions
How long does passionflower take to work?
In trials before a procedure, a single dose 30 to 90 minutes beforehand was enough to measure a difference in anxiety. For sleep, trials lasted one to two weeks. If there is no improvement beyond that, it is better to discuss it with a healthcare professional.
Can you combine passionflower and valerian?
These combinations are common, but the trials cited here concern passionflower alone. The sedative effects of the two plants may add up: avoid driving after taking them and do not combine them with a sleeping tablet.
What is the difference between passionflower and passion fruit?
Passion fruit comes from another species, Passiflora edulis, and is consumed as a food. Studies on stress and sleep concern the aerial parts of Passiflora incarnata: eating passion fruit does not provide these preparations.
Is passionflower harmful to the liver?
The European monograph mentions no adverse liver effects, and the 2020 review reports no notable adverse effects in trials. As with any plant, jaundice, dark urine or unusual fatigue should prompt you to stop taking it and seek medical advice.
Is passionflower addictive?
The sources consulted do not describe dependence, but trials lasted only a few weeks at most. They therefore cannot assess prolonged use: the claim that the plant carries no risk of dependence is not proven.
Passionflower or melatonin: what is the difference?
Melatonin is a hormone with an authorised health claim: it contributes to reducing the time taken to fall asleep, with 1mg taken before bedtime. Passionflower is a plant without an authorised claim, whose use for sleep is traditional. Our article on sleep and melatonin explains these differences.
Conclusion
The benefits of passionflower commonly highlighted primarily relate to traditional use, recognised in Europe for herbal medicines (mild symptoms of stress, aiding sleep); no health claim is authorised for food supplements. Clinical trials support the direction of this traditional use, particularly for anxiety before a procedure, but are too few and too small to constitute strong evidence. Although well tolerated in these studies, the plant may cause drowsiness: take care when driving and with sedatives, and avoid use during pregnancy and breastfeeding. To place it alongside other approaches, see our guide to stress and the ingredients studied in this area and our article on ashwagandha.
Sources
- European Medicines Agency, HMPC (2014). Community herbal monograph on Passiflora incarnata L., herba. EMA/HMPC/669740/2013. ema.europa.eu
- European Medicines Agency, HMPC (2014). Assessment report on Passiflora incarnata L., herba. EMA/HMPC/669738/2013. ema.europa.eu
- Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods. Official Journal of the European Union, L 136, 1-40. eur-lex.europa.eu
- Appel K et al. (2011). Modulation of the γ-aminobutyric acid (GABA) system by Passiflora incarnata L. Phytotherapy Research, 25(6), 838-843. doi:10.1002/ptr.3352
- Movafegh A et al. (2008). Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study. Anesthesia & Analgesia, 106(6), 1728-1732. doi:10.1213/ane.0b013e318172c3f9
- Aslanargun P et al. (2012). Passiflora incarnata Linneaus as an anxiolytic before spinal anesthesia. Journal of Anesthesia, 26(1), 39-44. doi:10.1007/s00540-011-1265-6
- Dantas LP et al. (2017). Effects of passiflora incarnata and midazolam for control of anxiety in patients undergoing dental extraction. Medicina Oral, Patología Oral y Cirugía Bucal, 22(1), e95-e101. doi:10.4317/medoral.21140
- Akhondzadeh S et al. (2001). Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. Journal of Clinical Pharmacy and Therapeutics, 26(5), 363-367. doi:10.1046/j.1365-2710.2001.00367.x
- Miyasaka LS, Atallah AN, Soares BG (2007). Passiflora for anxiety disorder. Cochrane Database of Systematic Reviews, (1), CD004518. doi:10.1002/14651858.CD004518.pub2
- Ngan A, Conduit R (2011). A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytotherapy Research, 25(8), 1153-1159. doi:10.1002/ptr.3400
- Lee J et al. (2020). Effects of Passiflora incarnata Linnaeus on polysomnographic sleep parameters in subjects with insomnia disorder: a double-blind randomized placebo-controlled study. International Clinical Psychopharmacology, 35(1), 29-35. doi:10.1097/YIC.0000000000000291
- Janda K et al. (2020). Passiflora incarnata in Neuropsychiatric Disorders: A Systematic Review. Nutrients, 12(12), 3894. doi:10.3390/nu12123894
- NCCIH (2025). Passionflower: Usefulness and Safety. National Center for Complementary and Integrative Health. nccih.nih.gov
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