Anti-inflammatory effect of chamomile from randomized clinical trials: a systematic review and meta-analyses

Abstract

Context: Chamomile is a widely recognized medicinal herb, and it has been used for its various medicinal properties. Chamomile's widespread recognition and application in medicine highlights its significance in herbal therapeutic practices globally.

Objective: To explore chamomile as a low-risk antimicrobial and anti-inflammatory agent, utilizing clinical characteristics derived from the existing body of evidence from randomized clinical trials within the current literature.

Methods: We conducted a systematic review of randomized clinical trials using the search terms 'chamomile anti-inflammatory antimicrobial randomized clinical trials' and 'chamomile anti-inflammatory antimicrobial'. We sourced data from databases including PubMed, Google Scholar, Cochrane Library, and ClinicalTrials.gov. We then performed a meta-analysis using R to assess the efficacy of chamomile as an anti-inflammatory and an antimicrobial agent, and its impact on mucosal recovery in clinical settings.

Results: A total of 11 randomized clinical trials were identified. The mean difference, confidence intervals, and standard error from the extracted means and standard deviations for relevant outcomes were calculated. Statistical tests from the meta-analysis demonstrated that chamomile exhibited statistically significant reductions in mucositis severity and pain level, indicating the anti-inflammatory effects of chamomile.

Conclusion: This study highlights chamomile's potential as a natural alternative for managing inflammation and microbial infections, offering a promising alternative to standard treatments. Our study suggests chamomile has the potential to act as a natural anti-inflammatory agent. A future study with a larger sample size may provide clinical evidence of this effect.

Systematic review registration number (PROSPERO): CRD42024566615.

Keywords: Chamomile; anti-inflammatory; natural herbal plant.

Figure 1.

Summary of traditional use of chamomile. This figure was created based on the collection of information from the previous reports (Antonielli , Benítez et al. , Carle and Gomma , Malik et al. , McKay and Blumberg , Menale et al. , Mrabti et al. , Naceiri Mrabti et al. , Raal et al. , Savikin et al. , Smitherman et al. , Tabernaemontanus , Ubessi et al. , Zucchi et al. 2013).

Figure 2.

Systematic review flow chart based on PRISMA-P guidelines, which outlines the study screening and selection process.

Figure 3.

A. Forest Plot for the meta-analysis of chamomile’s anti-inflammatory effects including outcomes of pain severity and bleeding. Seven studies were included. The pooled mean difference was -1.57 (95% CI: -4.05 to 0.91) with no statistically significant effect. High heterogeneity was noted (I² = 92%, p < 0.01), B. Forest plot for the meta-analysis of chamomile’s reduction of pain severity levels. Four studies were included in the Sub-analysis evaluating chamomile’s effect on pain severity levels. The pooled mean difference was -0.61 (95% CI: -0.76 to -0.46) and showed a statistical significance. No heterogeneity was noted (I² = 0%, p = 0.95) while variation of effect size was observed due to limited number of study available. C. Forest plot for meta-analysis of chamomile’s effect on pain severity levels on oral mucosa included rest of three studies. The pooled mean difference was -3.09 (95% CI: -13.55 to 7.37). Additionally, there was no significant heterogeneity among the studies analyzed (I² = 97%, p < 0.01). The red diamond shape represents the average effect with confidence intervals as its width while the black vertical line represents no significance.

Figure 4.

Forest Plot for the meta-analysis of chamomile’s antimicrobial effects. For chamomile’s antimicrobial properties, five studies were selected and analyzed. The pooled mean difference was -3.90 (95% CI: -10.94 to 3.13) which indicated no significant antimicrobial effect. High heterogeneity was observed (I² = 95, p < 0.01). The red diamond shape represents the average effect with confidence intervals as its width while the black vertical line represents no significance.

Figure 5.

A. Forest Plot for the meta-analysis of chamomiles’ gingival index. Three studies were included. The pooled mean difference was -1.25 (95% CI: -3.46 to 0.96), indicating no significant effect. High heterogeneity was noted (I² = 83%, p < 0.01). B. Forest plot for the meta-analysis of chamomile’s reduction of mucosal inflammation. Three studies were included. The pooled mean difference was -0.70 (95% CI: -1.25 to -0.15), indicating a significant effect. No heterogeneity was noted (I² = 0%, p = 0.58) while variation of effect size was observed due to limited number of study available. The red diamond shape represents the average effect with confidence intervals as its width while the black vertical line represents no significance.

Figure 6.

Summary of chamomile components and medicinal effects displayed by alluvial diagram. Each component of chamomile displays intercalation with multiple medicinal effects. The figure was restructured based on information included in the review article by Akram et al. (2024).