To investigate the main component and mechanisms of Mongolian Medicine bear bile in the treatment of stress ulcer hemorrhage model rats.Methods:A total of 104 SD rats were randomly divided into 13 groups, namely blank group, model group, Caffeic acid positive group, mongolian Hemostasis Honghua-8 pill low and high dose group, bear bile low and high dose group, UDCA low and high dose group, TUDCA low and high dose group, CA low and high dose group, 10 rats in each group.The rats were treated by sequential administration.The impact of Platelet, 5-hydroxy tryptamine (5-HT), angiotensinⅡ (AngⅡ) and vascular endothelial growth factor (VEGF) and the pathological changes was observed and analyzed.Results:Compared with the blank group, the content of platelet reduced.5-HT, AngⅡ and VEGF were significantly increased, which was statistically significant (P<0.05).Compared with model group, bear bile and the main component of platelet increased in blank group, positive group, Mongolian Medicine treatment group, and 5-HT, AngⅡ and VEGF were showing significantly decreasing tendency (P<0.05).Compared with the Omeprazole positive group, except for CA low and high dose groups, Mongolian bear bile and its main effective component of 5-HT, AngⅡand VEGF were not significantly different (P>0.05).The effects of the UDCA and TUDCA groups were particularly significant.Under light microscope, the structure of gastric mucosa and gastric fundus gland of rats in the blank group were connected, and the ulcer in the model group was significantly improved.Conclusion:Mongolian bear bile and its main components, UDCA and TUDCA, have a good treatment and prevention of gastric ulcer bleeding.The main effective components of Mongolian bear bile in the treatment of gastric ulcer bleeding are UDCA and TUDCA, but the effect of CA was weak.