Pelargonium sidoides for acute bronchitis: a systematic review and meta-analysis.

OBJECTIVE: To critically assess the efficacy of Pelargonium sidoides for treating acute bronchitis. DATA SOURCES: Systematic literature searches were performed in 5 electronic databases: (Medline (1950 - July 2007), Amed (1985 - July 2007), Embase (1974 - July 2007), CINAHL (1982 - July 2007), and The Cochrane Library (Issue 3, 2007) without language restrictions. Reference lists of retrieved articles were searched, and manufacturers contacted for published and unpublished materials. REVIEW METHODS: Study selection was done according to predefined criteria. All randomized clinical trials (RCTs) testing P. sidoides extracts (mono preparations) against placebo or standard treatment in patients with acute bronchitis and assessing clinically relevant outcomes were included. Two reviewers independently selected studies, extracted and validated relevant data. Methodological quality was evaluated using the Jadad score. Meta-analysis was performed using a fixed-effect model for continuous data, reported as weighted mean difference with 95% confidence intervals. RESULTS: Six RCTs met the inclusion criteria, of which 4 were suitable for statistical pooling. Methodological quality of most trials was good. One study compared an extract of P. sidoides, EPs 7630, against conventional non-antibiotic treatment (acetylcysteine); the other five studies tested EPs 7630 against placebo. All RCTs reported findings suggesting the effectiveness of P. sidoides in treating acute bronchitis. Meta-analysis of the four placebo-controlled RCTs suggested that EPs 7630 significantly reduced bronchitis symptom scores in patients with acute bronchitis by day 7. No serious adverse events were reported. CONCLUSION: There is encouraging evidence from currently available data that P. sidoides is effective compared to placebo for patients with acute bronchitis.