Studies on Wistar rats have demonstrated that six months after ovariectomy no changes were observed in peripheral blood morphology other than a decreased leukocyte count. A similar effect was noted in the sham-operated group. The present results show that Ukrain treatment started on the second postoperative day and continued every other day for six months significantly increased leukocyte count in comparison with the untreated ovariectomized and sham-operated groups. The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also estimated in this study. In none of the groups studied was any change of ALT activity noted. The activity of AST was significantly increased in the sham-operated and untreated ovariectomized rats. After six-month treatment with Ukrain, the activity of this enzyme was significantly decreased in the serum of untreated ovariectomized rats. In rats pretreated with Ukrain some of the studied parameters of peripheral blood were similar to those of the control group.