Efficacy of chamomile in pain relief: A systematic review and meta-analysis of clinical trials

Background: Chamomile is a well-known medicinal herb traditionally used for its analgesic properties. This article aims to provide an updated and critical evaluation of evidence from randomized controlled trials (RCTs) on chamomile’s efficacy for pain relief. Methods: A comprehensive literature search was conducted in Medline, Embase, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials for published RCTs from inception to December 2024. Inclusion criteria comprised RCTs investigating chamomile in any form (oral, inhalation, or topical) compared to placebo or active controls, assessing pain as a primary outcome using validated tools such as the Visual Analog Scale (VAS), Numeric Rating Scale (NRS), or McGill Pain Questionnaire. Standardized mean differences (SMDs) with 95 % confidence intervals (CIs) were calculated using random-effects models. Results A systematic search identified 18 randomized controlled trials (n = 1,525) evaluating chamomile for pain relief. Meta-analysis demonstrated that chamomile was associated with significant pain reduction versus controls (SMD = −0.96; 9 5% CI: −1.36 to −0.57; P < 0.001), with high heterogeneity (I² = 91.1 %). Subgroup analyses showed significant effects in trials that used the Visual Analog Scale (VAS: SMD = −1.12, P < 0.001), with non-significant effects for other pain scales. Chamomile was superior to placebo (SMD = −0.95, P < 0.001) but did not differ significantly from other active treatments (P = 0.074). Conclusion This meta-analysis provides evidence supporting the analgesic efficacy of chamomile. However, substantial heterogeneity across studies suggests variability in design, populations, and protocols, warranting cautious interpretation. Future high-quality, standardized RCTs are needed to clarify effects by formulation, dosing, and clinical context.