On 39 cases of parathion poisoning treated with PAM (pyridine-2-aldoxime methiodide) the author obtained the following results. 1. From cholinesterase determinations and clinical findings PAM has been found to be the most effective drug available at present for the treatment of parathion poisoning. 2. The effect appears promptly within 30--40 minutes of the treatment. 3. By administering PAM such symptoms as disturbance of consciousness, muscular fasciculation, salivation, bronchial secretion, convulsions, vomiting, and rasping in the lung, all disappear easily. Apart from these there may persist for quite same time such subjective symptoms as headache, miosis, pallor, quick breathing, speech difficulty, slow pupillary reflex, and numbness of limbs, but these are not dangerous. 4. If no improvement at all occurs after the administration of PAM, the case may be suspected as not paration poisoning. 5. As for the method of administration, 1.0 g PAM (40 ml 2.5% aqueous solution) is administered intravenously, and if no prompt effect appears another dose of 1.0 g PAM will be sufficient. 6. Occasionally vomiting accompanies the PAM injection, but it is considered as due to parathion, and there can be observed otherwise no other side-effect. 7. There is no need of concurrent use of atropine, and even in severe case the dose of atropine should be limited to 0.5-1.0 mg to suppress secretion. The use of a large amount of atropine, on the contrary, brings about the danger of atropine poisoning. 8. In extremely severe cases where even 2.0 g PAM shows little effect, PAM in the amount up to 4-5 g may be additionally given along with atropine.