Abstract: Objective Fine pigment granules in livers and kidneys of SD rat induced by geniposide were differentially diagnosed in this report.Methods A gross observation was performed on liver and kidney of SD rats which were administrated geniposide by oral gavage,and routine HE staining slides for microscopic analysis was carried out.In addition,the blood biochemical and urine index in clinical pathology were analyzed,and special staining was used for differential diagnosis.Result Compared to the control group,livers and kidneys of SD rats in each dose group were found discoloration of gray green,as well as the serum TB and GGT was increased significantly (P<0.05).The contents of urine URO and BIL in dose group were increased with dose-relation.Microscopically,liver and kidneys in all dose group animals were found tiny brown-yellow pigment droplets which were test material related.These pigment particles were positive for Fouchet staining but negative for Perls blue.Conclusion In this case,the bilirubin pigmentation was definitely diagnosed by using clinical pathology data combination with histopathological examination.In addition,the relationship between histopathologic changes of livers and kidneys and clinical pathology was explained.This can provide theory and method on pigmentation differential diagnosis for future toxicologic pathology work.

Key words: Bilirubin, Pigment, Toxicologic histopathology