目的：研究阿莫西林预防大鼠半胱胺十二指肠溃疡的作用机制。方法：采用超声多普勒血流测定仪检测阿莫西林及半胱胺对大鼠胃十二指肠粘膜血流的影响；并测定阿莫西林灌胃后大鼠十二指肠粘膜前列腺素Ｅ＿２的变化。结果：阿莫西林可增加大鼠胃十二指肠粘膜血流，并防止半胱胺诱发的十二指肠粘膜血流下降；该药灌胃后十二指肠粘膜前列腺素Ｅ＿２有高于对照组的趋势。结论：增加十二指肠粘膜血流可能是阿莫西林预防大鼠半胱胺十二指肠溃疡的重要机制之一；阿莫西林有增加大鼠十二指肠粘膜前列腺素Ｅ＿２合成的趋势。 Objective: To study the mechanism of amoxicillin in preventing cysteamine duodenal ulcer in rats. Methods: The effects of amoxicillin and cysteamine on gastroduodenal mucosal blood flow in rats were measured by Doppler flowmetry, and the levels of mucosal prostaglandin E_2 changes. Results: Amoxicillin can increase gastric mucosal blood flow and prevent cysteamine-induced decreased duodenal mucosal blood flow; duodenal gonadal prostaglandin E2 after oral administration of the drug is higher than The trend of the control group. Conclusion: Increasing duodenal mucosal blood flow may be one of the important mechanisms of amoxicillin in preventing cysteamine duodenal ulcer in rats. Amoxicillin may increase the synthesis of prostaglandin E_2 in rat duodenal mucosa .