By selecting 4 oxime compounds possessing pyridine nucleus in the molecular construction, namely, PATD, PPATD, PPAPD, and PAD, the author compared their therapeutic effects on alkylphosphate poisoning with the effect of PAM. 1. As for the therapeutic effect on alkylphosphate poisoning in mice, when administered in the maximum safety dose, PATD and PPATD are superior to PAM, but on scrutinous examinations there can be recognized not any significant difference. Effect of PPAPD is about the same as that of PAM. 2. Both PAM and PATD are most effective when administered concurrently with the intravenous administration of alkylphosphate, but as the time before or after the administration of alkylphosphate lengthens, the effect of drugs decreases proportionately. 3. Atropine used concurrently with these oxime compounds yields no better results than without it. 4. The effect of PATD is slightly more lasting than PAM, but the difference is not significant. 5. PATD has been proven to possess a reactivating action on rabbit blood cholinesterase just as PAM. Consequently it is assumed that the effective mechanism of both drugs is same. 6. When an equal dose of PAD and PAM is administered to the mice with ethylparathion poisoning, PAD is inferior to PAM in improving the mortality rate of the mice. 7. There seems to be no benefit in administering intramuscularly 15 mg/kg PAD concurrently with the administration of various oximes.