Abstract: OBJECTIVE Integral animal experiment was employed to investigate the limonin distribution in different parts of rats’ intestine. METHODS The concentration of limonin in different parts of the intestinal was detected by LC-MS/MS method. After the rats were given the limonin 80mg/kg ig， the drug concentrations in the duodenum， small intestine and rectum were detected at 2，3，4，6 and 8h. RESULTS Limonin was highly distributed in different parts of the intestinal tissue. Most of intestinal tissue reached peak concentration at 3~4h after administration. The drug concentration in the duodenum and rectum was the highest， with duodenum being the second. CONCLUSION Limonin has a wide distribution and high concentration in rat intestine， and it plays a direct role in the treatment of hemorrhoids in intestine.