In spite of the radical increase of chemical poisoning cases caused by prevalent of oranic chlorine like endosulfan, the study of detection of chemical poisoning has seldom been attempted; the study of poisoning in teeth, which is more secure physiochemically, and in all the oral tissues has been even less attempted. The author has administered endosulfan into the month of a rabbit, causing its death, and tried to detect endosulfan in the teeth, jaws, and oral tissues through forensic chemical and histopathological tests. The result obtained is as follows : 1. By thin layer chromatography, endosulfan was detected in the jews, dental hard tissues, dental pulp, blood, and the liver. 2. By gas chromatography, it was also detected in the jaws, dental hard tissues, dental pulp, blood, and the liver. 3. The congestion and hemorrhage in buccal mucosa, palatal mucosa, and dental pulp was detected.