Passionflower
Passionflower is a climbing vine native to the southeastern United States and Central and South America. It has traditionally been used as a sedative. NCCIH says it might help to reduce symptoms of anxiety and might improve total sleep time in adults with insomnia, but its effects on falling asleep and staying asleep are mixed.
Passionflower is a climbing vine that is native to the southeastern United States and Central and South America. Traditionally, passionflower has been used as a sedative.
Research & evidence
Strong support Some support Weak or no supportColours show how well the sources back each point. The reason is next to each one.
A small amount of research suggests that oral passionflower might help reduce symptoms of anxiety, and anxiety before a surgical or dental procedure, but conclusions are not definite (NCCIH). MSK says preoperative use was reported to reduce anxiety.
Limited evidenceSome support. Based on one or a few small trials
Study details
NCCIH: "might help to reduce symptoms of anxiety and anxiety before a surgical or dental procedure," MSK: "preoperative use of passionflower was reported to reduce anxiety."
Source: NCCIH, Passionflower (Last Updated April 2025), What Have We Learned?; MSK About Herbs, Passionflower (Updated Thursday, April 13, 2023), Research Findings View source
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.
Mixed evidenceSome support. Results are mixed
Study details
NCCIH: "might improve total sleep time in adults with insomnia," NCCIH: "its effects on the time it takes to fall asleep and stay asleep are mixed."
Source: NCCIH, Passionflower (Last Updated April 2025), What Have We Learned? View source
In healthy adults, a low-dose passionflower tea produced short-term benefits in sleep quality (MSK).
Limited evidenceSome support. Based on one or a few small trials
Study details
MSK: "A small study showed benefits of passionflower in sleep quality in healthy adults."
Source: MSK About Herbs, Passionflower (Updated Thursday, April 13, 2023), Research Findings View source
A small study in children suggests passionflower may reduce ADHD symptoms (MSK), but NCCIH says there isn't enough evidence to say whether it helps ADHD.
Mixed evidenceSome support. Results are mixed
Study details
MSK: "A small study in children suggests that passionflower may reduce ADHD symptoms"
Source: MSK About Herbs, Passionflower (Updated Thursday, April 13, 2023), Research Findings View source
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.
Limited evidenceSome support. Not enough good evidence to say
Study details
NCCIH: "There is not enough evidence to say whether passionflower is helpful for any other health conditions."
Source: NCCIH, Passionflower (Last Updated April 2025), What Have We Learned? View source
Dosage
| Form | Amount |
|---|---|
| Any form | No standard dose is listed by our sources. |
Side effects
Possible side effects include drowsiness, dizziness and confusion. Large doses may result in central nervous system depression and slowed or irregular heart rhythms. NCCIH says passionflower should not be used during pregnancy.
Well documented Reported (case reports, anecdotal or one study) None reportedThe circle shows how well documented an effect is, not how serious it is. A rarely reported effect can still be serious, so always read ‘When to stop’.
| Effect | Frequency | When to stop |
|---|---|---|
| Drowsiness, dizziness or confusion; MSK also lists poor muscle coordination, allergic reactions and impaired thinkingWell documentedListed plainly by NIH, MSK or LiverTox | Not stated | Stop and talk to a doctor if it persists. Don't drive if you feel drowsy or dizzy. |
| Central nervous system depression and slowed or irregular heart rhythms with large dosesWell documentedListed plainly by NIH, MSK or LiverTox | Not stated | Stop and get medical help right away. |
Safety & interactions
Safety
NCCIH says passionflower is likely safe when it's used as a flavoring in food, and may be safe when it's taken as a tea for up to 7 nights. It says the daily use of passionflower extract may be safe for up to 8 weeks. Whether it's safe to use passionflower topically (on skin) is not known. MSK says large doses may result in central nervous system depression and slowed or irregular heart rhythms.
Contraindications
NCCIH says passionflower should not be used during pregnancy, and that little is known about whether it's safe to use while breastfeeding. MSK says passionflower should be avoided during pregnancy because it may cause uterine contraction and behavioral dysfunction in offspring. MSK says not to take passionflower if you take drugs that prolong the QT interval (for example azithromycin, dasatinib or fingolimod): lab analyses suggest passionflower may also prolong the QT interval with large doses, and it is not known whether it may add to the heart effects of these medicines. NCCIH says to avoid passionflower before surgery unless a health care provider recommends it, and to talk to your provider if you're taking it within 2 weeks of a scheduled surgery.
Drug interactions
NCCIH says passionflower might interact with some anesthesia drugs, so avoid it before surgery unless a health care provider recommends it; taken with anesthesia or other medicines used around surgery, it might slow down the nervous system too much. Talk to your health care provider if you're taking it within 2 weeks of a scheduled surgery.
MSK says passionflower may potentiate the effects of pentobarbital.
MSK says passionflower may increase the sedative effects of benzodiazepines.
MSK says passionflower was shown to enhance the potency of St. John's wort; the clinical significance is not known.
MSK says not to take passionflower with drugs that prolong the QT interval. Lab analyses suggest passionflower may also prolong the QT interval with large doses, and it is not known whether it adds to the heart effects of these medicines.
Established: stated plainly by an authoritative source. Documented: supported by case reports or trial data. Theoretical: based on mechanism, animal data, or a cautious listing. Always check with your pharmacist or prescriber.