The excitability of anterior horn cells was examined with an analysis of Magladery H-wave obtained by the method of provocation E. M. G. under Fluothane, Ether and Thiopentobarbital anaesthesias. Twenty-six adults in both sexes were selected for this study in which no abnormal findings were foune. H-wave was obtained at gastrocnemius muscle under awake and anaesthetized stages, and recovery curves were made of H-wave amplitudes responded to successive stimuli of conditioning and testing through posterior tibial nerve. Prolongation of the duration of complete depression at the recovery curve or decrement of the excitability was found under Fluothane and Ether, and in contrant, no change of the excitability was found in case of Thiopentobarbital anaesthesia. No variation of M-wave was found in all cases of the anaesthesias, which revealed no influence on peripheral nerves and muscle fibers.