Hypothesis
Chamomile, the most commonly used herbal remedy for sleep problems, would improve subjective sleep in chronic primary insomnia.
What failed
In 34 patients randomized for 28 days, there were no significant between-group differences in any sleep-diary measure: total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sleep quality or number of awakenings. Effect sizes were small to moderate, and total sleep time favoured placebo.
Broken assumption
Chamomile’s long-standing reputation as a sleep aid shows up in measured sleep.
Why
The authors describe the daytime-functioning advantages as modest and not significant, and call for trials in selected insomnia patients.
From the published paper: Zick et al. BMC Complementary and Alternative Medicine, 2011. ↗CC BY