This article introduces two cases, in which the result of toxicological analysis provides the important clue to investigator and the evidence to the justice for one case, while the result of toxicological analysis provides the basis for emergency treatment methods for another case. The article introduces two problems of toxicological analysis during the extraction. One is the microanalysis, and the other is how to clear out the protein and fat from biological material. The article thinks that the present level of toxicological analysis for some techniques in China is near that of the developed country in the end of the 20th century, but the standard management is China lags behind. In the future, the development of toxicological analysis should be in accordance with domestic reguirement and aimed at new techniques in the world.