Objective:To evaluate the effect of Buyang Huanwu Decoction(补阳还五汤,BYHWD) on glial scar after intracerebral hemorrhage (ICH) and investigate the underlying mechanism.Methods:Collagenase type Ⅶ (0.5 U) was injected stereotaxically into right globus pallidus to induce ICH model.One hundred and twenty Sprague-Dawley rats were randomly divided into 3 groups according to a random number table,including normal group (n=40),ICH model group (n=40) and BYHWD group (n=40),respectively.After ICH,the rats in the BYHWD group were intragastrically administered with BYHWD (4.36 g/kg) once a day for 21 days,while the rats in ICH group were administered with equal volume of distilled water for 21 days,respectively.Double immunolabeling was performed for proliferating cell nuclear antigen (PCNA)+/glial fibrillary acidic protein (GFAP)+ nuclei.The expression of GFAP and leukemia inhibitory factor (LIF) was evaluated by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR).Results:The astrocytes with hypertrophied morphology around the hematoma was observed on day 3 after ICH.The number of GFAP positive cells and GFAP mRNA levels increased notably on day 3 and reached the peak on day 14 post-ICH (P＜0.01).PCNA+/GFAP+ nuclei were observed around the hematoma and reached the peak on day 14 post-ICH (P＜0.01).In addition,LIF-positive astrocytes and LIF mRNA level in the hemorrhagic region increased significantly till day 14 post-ICH (P＜0.01).However,BYHWD not only reduced the number of PCNA+/GFAP+ nuclei,but also decreased GFAP and LIF levels (P＜0.05).Conclusion:BYHWD could attenuate ICH-induced glial scar by downregulating the expression of LIF in the rats.