This study featured a double-blind, placebo-controlled, repeated-measures design with a counterbalanced order of treatments (passionflower vs placebo tea), separated by a 1‚Äâweek ‚Äòwashout‚Äô period. Forty-one participants (18‚Äì35‚Äâyears) were exposed to each treatment for a week, whereby they consumed a cup of the tea and filled out a sleep diary for 7‚Äâdays, and completed Spielberger's state-trait anxiety inventory on the seventh morning. Ten participants also underwent overnight PSG on the last night of each treatment period. Of six sleep-diary measures analysed, sleep quality showed a significantly better rating for passionflower compared with placebo (t(40)‚Äâ=‚Äâ2.70, p‚Äâ<‚Äâ0.01). These initial findings suggest that the consumption of a low dose of Passiflora incarnata, in the form of tea, yields short-term subjective sleep benefits for healthy adults with mild fluctuations in sleep quality. Copyright ¬© 2011 John Wiley & Sons, Ltd.