Passionflower

📜 Historical Use

NCCIH tells the history in three sentences, and the through-line is a single indication: "Traditionally, passionflower has been used as a sedative. Sixteenth-century Spanish explorers in South America learned of passionflower. The plant was then brought to Europe, where it became widely cultivated and was introduced to European folk medicine." The plant is a climbing vine with white and purple flowers, native to the southeastern United States and to Central and South America, and its older English name maypop still survives alongside apricot vine, maracuja and water lemon. What is striking about that record is how narrow it is. One traditional use is reported - sedative - and it is the same use that carries whatever modern evidence exists. The contemporary marketing is much wider: "Today, passionflower is promoted as a dietary supplement for anxiety (including anxiety before surgery), sleep problems, stress, attention-deficit hyperactivity disorder (ADHD), pain, and other conditions." Promoted is NCCIH's word, and it is not a synonym for shown. Of the items on that list, NCCIH reports that there is not enough evidence to say whether passionflower helps with stress or ADHD; pain is not addressed in its findings section except through fibromyalgia, which is also listed as having insufficient evidence; and the anxiety and sleep findings are each described as resting on a small amount of research.

📊 What the Research Shows

NCCIH states the overall position first: "Passionflower's effect on anxiety and other conditions hasn't been studied extensively." On the use this page is filed under, its finding is real but heavily qualified: "A small amount of research suggests that oral passionflower might help to reduce symptoms of anxiety and anxiety before a surgical or dental procedure, but conclusions are not definite." Two hedges in one sentence - a small amount of research, and conclusions that are not definite. On sleep the shape of the evidence is the opposite of how the herb is usually sold: "A small amount of research suggests that oral passionflower might improve total sleep time in adults with insomnia, but its effects on the time it takes to fall asleep and stay asleep are mixed." Total sleep time, not falling asleep faster. Everything else is negative or absent: "There is not enough evidence to say whether passionflower is helpful for any other health conditions, including ADHD, congestive heart failure, menopausal symptoms, fibromyalgia, and stress." Stress is on that list despite being one of the uses NCCIH says passionflower is promoted for. One further absence was checked deliberately. NCCIH's separate fact sheet on sleep disorders carries a dedicated Herbs section that discusses chamomile, kava and valerian by name; passionflower does not appear anywhere on that page.

Steep 1 tbsp dried passionflower in hot water for 10 min. Drink 2-3x daily or before bed.

May cause drowsiness. Avoid with MAOIs and sedatives.

⚠️ What happens if taken in excess:

The serious signal here is obstetric, not organ toxicity, and NCCIH states it as a prohibition rather than a caution: "Passionflower should not be used during pregnancy as it may induce uterine contractions and possibly lead to other problems." Little is known about whether it is safe while breastfeeding. The second signal is sedation around surgery: "Taking passionflower when also receiving anesthesia or other medications used before and after surgery might slow down the nervous system too much. Talk to your health care provider if you are taking passionflower within 2 weeks of a scheduled surgery." NCCIH's general perioperative guidance goes further, noting that supplements may affect "your response to anesthetics or to other medicines", may increase bleeding risk, and may cause "serious changes in your heart rate or blood pressure", and that some providers ask patients to discontinue all herbal supplements several weeks before elective surgery. Ordinary side effects are drowsiness, dizziness and confusion. On quantity NCCIH gives ceilings of time, not of amount: "Passionflower may be safe when it's taken as a tea for up to 7 nights, and the daily use of passionflower extract may be safe for up to 8 weeks." It also says passionflower "is likely safe when it's used as a flavoring in food", and that whether it is safe used topically on skin "is not known". No source read here reports liver injury, cardiotoxicity or neurotoxicity for passionflower.

NCCIH's passionflower fact sheet names exactly one interaction, and it names no individual drug: passionflower "might interact with some anesthesia drugs, so avoid its use before surgery unless recommended by a health care provider", with a two-week window before scheduled surgery for raising it with a clinician. A drug class alone is not usable at the pharmacy counter, so here is what that class means in NCCIH's own vocabulary. Its Know the Science module gives a worked example of a sedative supplement increasing a sedative drug, and that example names drugs: "Ashwagandha seems to have sedative effects, and there is some preliminary evidence that it may increase the effects of some benzodiazepines (Valium) and other sedatives and anti-anxiety drugs, including Xanax." That sentence is about ashwagandha. NCCIH has made no such finding for passionflower, and it is quoted here only to show what a sedative-on-sedative interaction looks like - which is directly relevant because this page's own summary likens passionflower to benzodiazepines. Several things are absent and should not be filled in: across the sources read, NCCIH names no cytochrome P450 enzyme for passionflower, no CYP3A4 or CYP2D6 involvement, no monoamine oxidase inhibitor interaction, and no alcohol interaction. Its instruction is general: "If you take any type of medicine, talk with your health care provider before using passionflower or other herbal products; some herbs and medicines interact in harmful ways."

1. Passiflora incarnata L. as anxiolytic before spinal anaesthesia — Movafegh A et al Anesth Analg (2008)[PubMed ↗]