A pilot study was made to elucidate the microbial flora of small intestine in patients of intestinal obstruction. A variety of microorganisms in intestinal obstruction patient is similar to that seen in the normal subjectz. But the number of microorganism is much higher in the intestinal fluid from patients with intestinal obstruction than in that from normal subjects. Culture of peritoneal fluid from the patients with intestinal obstruction shows no growth of microorganisms. Present study was carried out as a pilot study for further extensive and intensive study of small bowel microf lova, and is not able to show any conclusion this time.