Objective:To study the effect of tetramethipyzine on protecting injured spinal cord.Methods:72 rates were divided randomly into three groups.The first group (A) included 8 rates was served as control.The second (B) and third group (C) had 32 rates in each.The injury at the level L8 spinal segment of the rates in group B and C were made by dropping a weight of 10 g from a high 5 cm after a total laminectomy from L8 segments.Rates in group C were given Tetramethipyazine while those in group B had the same volume of nomal saline.At 1,6,12,24 hours following surgery,8 rates in each group were sacrificed and the injured segments were resected for examination.The content of water and electrolyte was measured by dry-wet method and atomic absorption spectroscopy.Results:A significant water,Ca 2+ and Na+ content increase in B and C group were seen by companision with pre-injury,but K+ decrease,while in group C the value of water and Ca 2+ and Na+ were significantly lower than that of group B.Conclusions:Tetramethipyazine can refrain the abnomal change of water and electrolyte in the injured spinal cord section of rates and has some effects on spinal cord in rat.