Derived from the aerial parts of the plant, passionflower is used by patients to treat insomnia, anxiety, epilepsy, neuralgia, and withdrawal syndromes from opiates or benzodiazepines. The active component of passionflower is unknown. The alkaloid components (e.g., harman, harmaline) are thought to produce monoamine oxidase inhibition, while other constituents, like maltol and gamma-pyrone derivatives, cause activation of GABA receptors (1). Theoretically, passionflower may potentiate the sedative effect of centrally acting substances (e.g., benzodiazepines, barbiturates, alcohol) (2). A small pilot study evaluated passionflower for generalized anxiety and showed comparable efficacy to oxazepam (3), but a systematic review concluded that randomized controlled studies are needed to confirm such effects (4). In patients undergoing surgery, preoperative passionflower use reduced anxiety (5). However, one study found that administration of five different Passiflora incarnata extracts to mice in their drinking water produced anxiogenic effects. Two of these extracts did show an anticonvulsant effect against pentylenetetrazol-induced seizures (6). Not all passionflower extracts are standardized because of which dosages and activities may vary. Reported adverse events include sedation, dizziness, impaired cognitive function, and one case report of nausea, vomiting, and ECG changes. Adverse events subsided following discontinuation of passionflower use (3) (7).