Abstract: 【Abstract】 Objective To investigate the effect and its possible mechanism on the digestive tract in rats of dual antiplatelet drugs .Methods 80 SD rats were randomly allocated into four groups:these experiment groups to give clopidogrel (7.81mg/kg.d,n=20),aspirin (10.41mg/kg.d,n=20) and clopidogrel combined aspirin (hereafter referred to dual antiplatelet,n=20) respectively. Each group had the intragastric administration once daily,blank group will give normal saline(n=20),meanwhile. All rats received operation after the final intragastric administration,then observed small intestinal injury,bacterial culture of jejunal fluid,small intestinal permeability test through EB,estimated the injury degree of small intestinal mucosa by HE staining.Results 1.Each experiment group rats’small intestinal mucosa have different degree of damage ,and pathological lesions were higher than the negative control group（P<0.05）,moreover,the dual antiplatelet group was the highest;2.Each experiment group rats’ small intestinal permeability increased obviously compared with the control group（P<0.05）,and the dual antiplatelet group was higher than both the aspirin group and the clopidogrel group （130.533±29.631vs90.965±3.765vs66.800±4.853,P=0.000)；3.The total bacteria of the dual antiplatelet group rats’ jejunal was apparently higher than the control group（61924.805±1751.159vs18154.280±1153.376,P=0.000）,and the ratio of enterobacterium and enterococcus decreased obviously in the dual antiplatelet group compared with the control group（0.220±0.089vs 1.007±0.148,P=0.000）.Conclusions Routine dose of dual antiplatelet drug aggravates the small intestinal injury degree of rats compared with a single drug. The increased intestinal bacteria ,dysbacteriosis, and increased small intestinal permeability may participate in the small intestinal mucosa damage process.

Key words: Dual antiplatelet drugs, Small intestinal injury, Permeability, Dysbacteriosis