Benefits
Calm before surgery or dental procedures
In two placebo-controlled trials before ambulatory surgery or spinal anesthesia, anxiety ratings were lower, or rose less, with oral passionflower than with placebo, without added sedation or slower psychomotor recovery. In a dental trial, anxiety fell within the passionflower group but not the placebo group. A fourth small dental trial found no difference from placebo on anxiety scales, though salivary cortisol was lower.
Anxiety scores over four weeks in adult outpatients
In a 4-week pilot trial in 36 adult outpatients with generalized anxiety disorder, 45 drops a day of a passionflower extract and the drug oxazepam both lowered anxiety scores, with no significant difference between them. There was no placebo group, and a Cochrane review judged the available trials too few to draw conclusions.
Total sleep time measured in a sleep lab
In a 2-week placebo-controlled trial in 110 adults with insomnia disorder, a passionflower extract increased total sleep time on overnight polysomnography more than placebo. Sleep efficiency and time awake after falling asleep improved within the passionflower group but did not differ from placebo.
Self-rated sleep quality with an evening tea
In a 1-week placebo-controlled crossover trial in 41 healthy adults aged 18 to 35, a cup of passionflower tea each evening improved self-rated sleep quality in sleep diaries compared with placebo tea. The other five sleep diary measures did not differ.
Mechanism of action
GABA system activity in lab studies
In rat brain tissue, a dry passionflower extract reduced GABA uptake and bound to GABA-A and GABA-B receptor sites, acting as a GABA-B antagonist in one assay. It did not affect the benzodiazepine or ethanol sites of the GABA-A receptor and did not change GABA release or breakdown. These are lab findings; how passionflower acts in people is not settled.
Flavonoids, alkaloids and other plant compounds
Passionflower contains alkaloids, phenolic compounds, flavonoids and cyanogenic glycosides. Its main flavonoids are apigenin, luteolin, quercetin and kaempferol, with flavonoid glycosides such as vitexin, isovitexin, orientin and isoorientin. A systematic review notes that the mechanism behind its effects has not been clarified.
Clinical trials
Pilot double-blind randomized trial: passionflower extract 45 drops a day plus placebo tablet, or oxazepam 30 mg a day plus placebo drops, for 4 weeks. (Akhondzadeh et al. 2001, J Clin Pharm Ther)
36 adult outpatients diagnosed with generalized anxiety disorder by DSM IV criteria (18 per group).
Anxiety scores fell in both groups, with no significant difference between them at the end of the trial. Oxazepam acted faster, and problems with job performance were more common on oxazepam. Without a placebo group, the trial cannot show how much of the change came from the extract.
Double-blind, placebo-controlled randomized trial of oral Passiflora incarnata 500 mg (Passipy, Iran Darouk) given 90 minutes before surgery. (Movafegh et al. 2008, Anesth Analg)
60 adults having outpatient surgery (30 passionflower, 30 placebo).
Anxiety ratings on a numerical scale were lower with passionflower than placebo (P < 0.001). Sedation, psychomotor recovery after surgery and time to discharge were similar in both groups.
Prospective, randomized, double-blind, placebo-controlled trial of oral Passiflora incarnata extract given before spinal anesthesia (a 700 mg/5 mL syrup, per a later systematic review). (Aslanargun et al. 2012, J Anesth)
60 adults aged 25 to 55 scheduled for spinal anesthesia.
The rise in state anxiety (STAI-S) just before spinal anesthesia was smaller with passionflower than with placebo. Psychomotor function, sedation scores, blood pressure, heart rate and side effects did not differ between groups.
Randomized, triple-blind trial with separate valerian, passionflower and placebo groups (not a combination); registered klRBR-6kcxvrc. (Velasquez et al. 2024, Oral Maxillofac Surg)
54 patients having two third molars extracted from one side of the jaw, split into three groups.
State anxiety (STAI) scores fell from before to after surgery within the passionflower group and within the valerian group, but not within the placebo group (p = 0.129). The abstract reports these within-group changes rather than a direct statistical comparison with placebo. Surgical discomfort did not change in any group, and vital signs varied.
Triple-blind randomized trial with placebo, midazolam 7.5 mg and Passiflora incarnata 260 mg groups, each given by mouth 30 minutes before surgery; publicly funded (PIBIC and CNPq, Brazil). (Lima Neto et al. 2025, Sci Rep)
30 healthy patients aged 16 to 35 having impacted third molars extracted (10 per group).
Anxiety questionnaire scores and most heart rate, blood pressure and oxygen readings did not differ among groups, and diastolic blood pressure was higher with passionflower. After surgery, salivary cortisol was lower with passionflower and with midazolam than with placebo.
Double-blind, placebo-controlled, counterbalanced crossover: one cup of passionflower or placebo tea each evening for a week, with a 1-week washout. (Ngan et al. 2011, Phytother Res)
41 healthy adults aged 18 to 35 with mild fluctuations in sleep quality; 10 also had overnight polysomnography.
Of six sleep diary measures, only sleep quality was rated better with passionflower tea than with placebo tea (p < 0.01). The other five diary measures did not differ.
Double-blind, randomized, placebo-controlled trial of a Passiflora incarnata extract for 2 weeks, with overnight polysomnography, sleep diaries and questionnaires. (Lee et al. 2020, Int Clin Psychopharmacol)
110 adults with insomnia disorder by DSM-5 criteria (mean age 40.5; 53.6% women).
Total sleep time on polysomnography increased more with passionflower than placebo (change 23.05 vs -0.16, P = 0.049). Sleep efficiency and wake after sleep onset improved within the passionflower group but did not differ from placebo.