From the clinical point of view, the effect of PAM are summarized as follows. 1) By the administration of PAM, there occured prompt and complete relief of the symptoms of poisoning. 2) The cholinesterase (ChE) activity of red blood cell was instantly and completely recovered and that of serum was transiently. 3) Generally a intravenous injection of 1g PAM was sufficent and it is to be added if necessary. 4) The side effect has not been experienced. 5) PAM had no influence to the ChE activity of normal blood. 6) PAM is expected to be used as the preventive agent of alkylphosphate poisoning.