Abstract: The relation between fat-soluble toxic components and residual insecticides in beans (phaseolus vulgaris L. ) was exploratively studied in this paper. The fat-soluble toxic components were extracted and cleaned up, then the toxicity of points selected from the cleaned-up toxic extracts was assayed,and the synergism of insecticides with them was tested as well. The results showed that all points obtained from various extraction systems decreased the toxicity when applied simultaneously with dimethoate, carbofuran, methami-dophos and decamethrin,except that point c from petroleum-ether system-F2 with dimethoate and carbofuran, and point a of F2 and point a from ether system-D with malathion increased slightly the toxicity to houseflies. Furthermore, all points by itself and with dimethoate had no influence on the tested mice.