The analytical method which is described enables to detect principal anticoagulants presently used in France as rodenticides. Its particularity lies in using a mixture of iso octane and dichloromethane 95/5 (V/V) in the extractive part whose output varies according to the compounds from 80 to 25 per cent in supplemented liver. Besides thin layer chromatography which is used to achieve identification and semi quantitative evaluation, spectrometric measurement can be carried through to confirm identity and precise quantity with more accuracy. Sensitivity varying according to compounds, it is possible to detect products whose minimum concentration in biological materials is between 1 and 5 ppm.