Background and ObjectiveBosentan therapy has been recommended for pulmonary arterial hypertension (PAH) and might be beneficial for chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to evaluate the specific effects of bosentan for PAH and CTEPH. Materials and MethodsWe performed a systemic review and meta-analysis of randomized controlled trials (RCTs), comparing efficacy and safety of bosentan treatment for PAH and CTEPH through major biomedical database. ResultsA total of 10 RCTs including 1185 patients were enrolled. For PAH patients, bosentan prolonged 6-minute walk distance with a weighted mean difference of 35.7m, reduced mean pulmonary arterial pressure by 5.7mm Hg, increased cardiac index by 0.4L/min/m(2), reduced pulmonary vascular resistance by 305.1dyn<bold>s</bold>/cm(5), prevented functional class from deterioration and reduced clinical worsening as compared with placebo. For CTEPH patients, bosentan improved cardiac index by 0.3L/min/m(2) and reduced pulmonary vascular resistance by 176.0dyn<bold>s</bold>/cm(5). Other efficacy outcomes regarding CTEPH did not attain statistical difference. For both PAH and CTEPH, there was no significant difference in mortality or adverse event between bosentan and placebo group. However, bosentan raised the risk of abnormal liver function in both PAH and CTEPH patients. ConclusionsBosentan is effective in treating PAH, whereas it improves only certain hemodynamic parameters of CTEPH. Incidence of liver function abnormality is higher in bosentan treatment.