The aim of the current study was to systematically assess the effectiveness of herbal medicines in treating chronic obstructive pulmonary disease (COPD).Randomised clinical trials (RCTs) testing herbal medicines against any type of control intervention in patients with COPD and assessing clinically relevant outcomes were included. The selection of studies, data extraction and validation were performed independently by at least two reviewers. Methodological quality was evaluated using the Jadad score. Effect sizes and their 95% confidence intervals were calculated.Fourteen eligible RCTs, testing 14 different herbal medicines, were located. Herbal medicines were compared against placebo or no treatment in six trials. Significant intergroup differences for one or more outcome were reported for several herbal medicines including Panax ginseng and Salvia miltiorrhiza. In seven RCTs, which compared herbal medicines with other herbal medicines, the results were mixed. A single trial compared a herbal medicine (Hedera helix leaf extract) with a conventional treatment (ambroxol tablet) and reported no significant difference between groups. Due to the heterogeneity of the data, statistical pooling was not performed. The median methodological quality score was 2 out of a possible maximum 5.The effectiveness of herbal medicines for treating chronic obstructive pulmonary disease is not established beyond reasonable doubt. Currently, the evidence from randomised clinical trials is scarce and often methodologically weak. Considering the popularity of herbal medicine among chronic obstructive pulmonary disease patients, rigorously designed studies seem warranted.KEYWORDS: Chronic bronchitis, chronic obstructive pulmonary disease, complementary therapy, herbal medicine C hronic obstructive pulmonary disease (COPD) is a group of conditions characterised by airflow obstruction [1]. Chronic bronchitis (CB) and emphysema are two major conditions within this group. COPD is a public health concern worldwide, and the prevalence of this disease is increasing. According to the World Health Organization report in 1998, COPD was the sixth leading cause of death and the twelfth most common cause of morbidity worldwide. Both the direct and indirect economic costs of COPD to the society are substantial. In the USA, 16 million people have symptomatic COPD incurring estimated total economic costs for COPD-related morbidity and mortality of US$23.9 billion [2]. In the UK, about 1.5 million patients suffer from COPD with a total annual cost to the National Health Service of ,£491 million for direct costs only and £982 million including indirect costs [1].There is no cure for COPD [3]. Current conventional treatment is aimed at relieving symptoms, preventing recurrent exacerbations, preserving optimal lung function and enhancing the quality of life [4]. Smoking cessation is the only therapeutic intervention shown to reduce disease progression [5]. Although the conventional management of COPD has been improved since the 1990s, the progres...