Acute bronchitis, an inflammation of the bronchiole tubes characterized by a productive cough, is one of the most common diagnoses in primary care. Viral infection is the primary cause of this condition; however, bacteria and allergens also play a role. Because antibiotics are ineffective at treating viral infections and are associated with adverse side effects and with resistance development because of misuse and overuse, alternative therapies for the treatment of acute bronchitis have gained increased focus. South African geranium (Pelargonium sidoides, Geraniaceae) is an herbaceous perennial popularly used in South African traditional medicine for the treatment of respiratory diseases. The objective of this study was to evaluate the evidence from clinical trials on the efficacy of a proprietary extract of South African geranium roots for treating acute bronchitis.

A systemic literature search was conducted to identify clinical trials of the efficacy of South African geranium published between 1950 and 2007 in 5 electronic databases: Medline, Amed, Embase, The Cochrane Library, and CINAHL. The following search terms were used: “acute bronchitis,” “Pelargonium,” “sidoides,” “Umckaloabo,” and “EPs_®7630.” The reference lists of the retrieved articles were also reviewed. Only randomized clinical trials that evaluated single preparations of South African geranium as sole or adjunctive oral treatments for acute bronchitis were included in the meta-analysis. Two reviewers independently assessed the retrieved articles to determine their eligibility for inclusion in the review.

Six randomized controlled trials met the inclusion criteria, of which four were suitable for statistical pooling; four of the studies were published. The meta-analysis was conducted using a fixed-effect model for continuous data, and each trial was evaluated for methodological quality and assigned a Jadad score (maximum possible score: 5). The 6 trials were categorized into one of 2 groups on the basis of the control intervention used: one trial evaluated South African geranium relative to conventional therapy (acetylcysteine), and the remaining 5 trials evaluated South African geranium relative to placebo. In all 6 trials, the South African geranium preparation used was EPs 7630 (Dr. Willmar Schwabe Pharmaceuticals, Karlsruhe, Germany). The methodological quality of the trials was “generally good.” Three of the trials had the maximum Jadad score of 5; one trial had a low score of 2. The results of all 6 trials suggested that EPs 7630 was effective at treating acute bronchitis. Four of the 5 placebo-controlled trials suggested that EPs 7630 significantly decreased bronchitis symptom scores after 7 days of treatment. No serious adverse effects were reported in any of the trials, but mild to moderate adverse effects were reported in all 6 trials. Reported adverse effects included gastrointestinal disorders, nervous system disorders, and ear and labyrinth disorders. Also reported were infections and infestations in trials involving children.

The authors of this study conclude that the meta-analysis yielded “encouraging evidence from currently available data that P. sidoides is effective compared to placebo for patients with acute bronchitis.” The mechanism of action thought to be responsible for the beneficial effects is the ability of EPs 7630 to antagonize bacterial adhesion and/or invasion of intact epithelia, thus protecting the upper respiratory tract from bacteria colonization and infection. The authors note that the study was limited by the relatively small number of studies reviewed.

—Brenda Milot, ELS