causes of death worldwide. Regenerative medicine as stem cells therapy is a newly rapidly developing field in which diseased tissues are regenerated. Aim: To evaluate the effectiveness of stem cell on liver degeneration induced by Chlorpyrifos as an organophosphorus insecticide widely used in agriculture in Egypt, and Comparing its efficacy with silymarin and colchicine as antifibrotic agents used in liver fibrosis. Methods: Induction of liver degeneration and fibrosis by Chlorpyrifos (CPF) for 8 weeks to Swiss albino mice in randomly divided groups (B, C and D) and a control healthy group (A), each group composed of 15 mice. Group (C) was treated with oral silymarin and colchicine and group (D) was treated with intra-peritoneal injection of Mesenchymal stem cells (MSC) (10 ⁶ cells / mouse) after induction of liver fibrosis. After 4 weeks of treatment, all mice were sacrificed, blood was collected for chemical analysis (liver functions tests: Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Albumin, Bilirubin). Histopathological evaluation and grading were assessed by H& E stain. Results: ALT, AST and Albumin were significantly improved in groups C and D. Bilirubin and liver tissue grading were significantly reduced in group D, with insignificant reduction in group C. Conclusion: Treatment with MSCs may improve liver functions tests (ALT, AST, Albumin, and Bilirubin) and liver fibrosis. While, treatment with colchicine and silymarin does not improve the liver fibrosis, nor improves total serum bilirubin, but may improve ALT, AST and Albumin.