The stability and toxicity test for p. p`-DDT, DDVP and dipterex that put to used sample in this study effects is follows A. about p. p`-DDT ① In elevating the stability of p. p`-DDT, best stabilizing solvent was benzene. ② The stability-agent has no difficulty as long as it not contain metal ion for instance Zn^(2+), Cr^(3+), Al^(3+), and Fe^(2+or3+) but in case of contain Fe^(3+), the combination of salicylaminoguanidine is best effective. ③ Using this product for water-suspension, We must use span 40 for stability agent and adding it at the same time. ④ We must use container which does not week alkali and metal ion but it is to preserved in tight light-resistant container. ⑤ The stopper of container is adapted with above-mentioned condition of container, but it is better not to use metal material. ⑥ This product needs opening ventilation mare than 30 minutes after diffusion or spray and in the room we remove cause of remained poison by cleaning the bottom. B. about DDVP and Dipterex ① Benzene or toluene in best solvent to preserve stability of DDVP and Dipterex. ② Span 40 is superior for stability agent of this product and second is span 80. ③ The pH of solution is very stable in pH 5-6 and comparative stable in alkali more than p, p`-DDT. ④ Container is to preserved in tight, lightresistant container and especially be careful of outflow and inflow of water. ⑤ Because this product is centeral stimulant poison, we must pay attention to prevent cause of contact diadermic toxicity after use.