Effects of chamomile (Matricaria chamomilla L.) on sleep: A systematic review and meta-analysis of clinical trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of clinical trials
PubMed 39106912 · doi:10.1016/j.ctim.2024.103071
What was done
A systematic review and random-effects meta-analysis was conducted across PubMed, Scopus, Web of Science, and Cochrane Library through August 2023 to evaluate the effects of chamomile (Matricaria chamomilla L.) on sleep in healthy or diseased adults. Study quality was evaluated using the Cochrane risk of bias tool. Random-effects meta-analysis was performed to pool weighted mean differences (WMD) and 95% confidence intervals for outcomes reported by at least three studies with relatively consistent participants.
What was found
Ten clinical trials comprising 772 participants were included. Meta-analysis of five studies showed a significant reduction in Pittsburgh Sleep Quality Index (PSQI) score (WMD: -1.88, 95% CI: -3.46 to -0.31, I2: 88.4%). Sleep onset latency or ease of getting to sleep improved in three of four studies, and awakenings after sleep improved in two of three studies. Daytime functioning measures (fatigue scales) showed no change across three studies. Sleep efficiency did not change in two studies and deteriorated in one. No adverse events were reported.
Why it matters
Chamomile moderately improves subjective sleep quality and nocturnal awakenings, though it does not appear to improve overall sleep duration, sleep efficiency, or daytime fatigue.
Limits
High heterogeneity was present for the meta-analyzed PSQI outcome (I2 = 88.4%). The total sample across all ten trials was modest (772 participants). Only one study tested product purity or potency and verified blinding success. Adverse events were largely monitored via passive surveillance rather than active assessment, and objective sleep measures were not evaluated.