Abstract
For the purpose of distinguihsing sumithion from methylparathion in the mammalian metabolism, phosphorus32 labeled compounds were administered to Guinea pig and white rat. Both compounds were found to be absorbed readily, and phosphorus containing metabolites excreted chiefly into urine. By chromatographic separation and identification of the metabolites, the decomposition of sumithion was observed to proceed presumably more easily than methylparathion. From these results lower toxicity of the former toward mammals than the latter was discussed. In addition, compounds remaining in rice plant and German cockroach were also analysed.