Some reports have shown that mesenchymal stem cells (MSCs) therapy could ameliorate chemically induced hepatic fibrosis. This research assesses the therapeutic action of bone marrow mesenchymal stem cells (BM-MSCs) on chronic diseased liver in Schistosoma mansoni infected mice. All infected female mice divided into three groups, one group (15 mice) treated with oral praziquantel (PZQ), second group (15 mice) received intravenous injection of BM-MSCs and third group (15 mice) treated with both MSCs ? PZQ. Two control groups (15 mice each) subdivided into one infected and second healthy one. BM-MSCs were obtained from bones of both femur and tibia of male mice (30 mice), then cultured and characterized morphologically by detection of CD105 by flow cytometer. Liver tissues for all groups were examined histopathologically. Measuring of the collagen 1 gene expression was done by real-time PCR and immunohistochemical study to detect stem cells differentiation for detection of MSCs engraftments in liver tissue. MSCs treatment caused marked improvement and regression of fibrosis, and prevents deposition of collagen and reduced the expression of collagen 1 gene in infected mice on their liver tissues, especially when used with PZQ in mice treatment. It can be concluded that, MSCs is a good therapeutic method for liver fibrosis caused by S.