Objective To investigate the tissue stimulation of copper ions to the smooth muscle of murine terminal rectum.Methods In this study copper needle used for electrochemical therapeutic equipment was punctured into submucosal smooth muscle tissue of terminal rectum above the dentate line in 65 male rats.Rats were then divided into 5 groups (10 rats in each group) at random and sacrificed at 1, 3, 4, 6, 8 weeks after respectively, samples were sent for observation of macroscopic and microscopic tissue reaction.Results Rats had no abnormal histological change in the puncture points grossly. Undor microscope, mild edema was detected in the submucosal layer in 1 week group. Remarkable infiltration of inflammatory cells and lymphocytes subsided 3 weeks after, and disappeared five weeks after.Smooth muscle was normal microscopically in all groups.In contrast, platinum and steel needles caused infiltration of plasma cells and neutrophils, ulcers and small abscess formation in around puncture points.Conclusion Inflammatory reaction was induced after puncturing of copper needle into the tissues and the tissue reaction disappeared after 5 Ws.In contrast with platinum and steel needles, copper needle was non-traumatic to the smooth muscle tissue.