It was established in experiments on Wistar rats that oral methyl mercuric iodide at doses of 0.85, 0.64, 0.42 and 0.21 mg/kg daily exerts no teratogenic or embryotoxic action on the progeny. However, administration of methyl mercuric iodide at doses of 0.85 and 0.64 mg/kg produced in females a significant decrease in the SH-group content in renal and cerebral tissues, in the activity of acetylcholine esterase in the cerebellum (by 18-48%) and a rise in the activity of glucose-6-phosphatase in the kidneys (by 48-70%). The doses of 0.42 and 0.21 mg/kg administered at various periods of pregnancy, did not exert any effect on the body of females under experimental conditions. These findings are supported to a certain measure by the results of examination of a 2-month progeny of the animals given 0.21 mg/kg methyl mercuric iodide daily. The biochemical parameters of these animals did not differ from those of the control ones.