Patients operated upon for small bowel obstruction generally require more than the usual amount of early postoperative salt and water administration to maintain an adequate urine flow. The accepted explanation is that the surgical trauma results in additional fluid shifts into the peritoneum, gut wall, and mesentery. Gendel and Fine in 19401,2 suggested that enterotomy minimized this shift by reducing distention. Our observations do not support this suggestion. We have noted that occasional patients undergoing surgical procedures for relief of small bowel obstruction have developed significant hypotension, tachycardia, and diminished urine flow shortly after surgery, or even during the late stages of operation. A review of our hospital records of simple small bowel obstruction has substantiated our impression that this hypotension occurs more frequently when enterotomy is performed in addition to lysis of adhesions. In every instance, when this hypotension was treated with relatively large amounts of colloid, blood,