A bowel resection or enterectomy (enter- + -ectomy) is a surgical procedure in which a part of an intestine (bowel) is removed, from either the small intestine or large intestine. Often the word enterectomy is reserved for the sense of small bowel resection, in distinction from colectomy, which covers the sense of large bowel resection. Bowel resection may be performed to treat gastrointestinal cancer, bowel ischemia, necrosis, or obstruction due to scar tissue, volvulus, and hernias. Some patients require ileostomy or colostomy after this procedure as alternative means of excretion. Complications of the procedure may include anastomotic leak or dehiscence, hernias, or adhesions causing partial or complete bowel obstruction. Depending on which part and how much of the intestines are removed, there may be digestive and metabolic challenges afterward, such as short bowel syndrome.

Types of enterectomy are named according to the relevant bowel segment:

The anatomy and surgical technique for bowel resection varies based on the location of the removed segment and whether or not the surgery is due to malignancy. The below sections describe resection for non-malignant causes. Malignancy may require more extensive tissue resection beyond what is described here.

Bowel resection may be done as an open surgery, with a long incision in the abdomen. It may also be done laparoscopically or robotically by creating several small incisions in the abdomen through which surgical instruments are inserted. Once the abdomen is accessed by one of these methods the surgery may proceed.

Once the abdomen is accessed, the surgeon "runs" the small bowel, viewing the entire small bowel from the ligament of treitz to the ileocecal valve. This allows for total evaluate of the small bowel to identify any and all pathologic sections. Once the area of concern is located, two small holes are created in the mesentery on either end of the segment. These holes are used to place a surgical stapler across the bowel and separate the segment of injured bowel from the healthy bowel on each end. Then bowel is then dissected away from the mesentery. Following this the remaining bowel is observed to verify continued blood flow. After resection the surgeon will create an anastomosis between the two ends of the bowel. Following this the hole in the mesentery created by removing the section of bowel is closed with sutures to prevent internal herniation. The resected section of bowel will then be removed from the abdomen and the abdomen closed. This concludes the procedure.

The right and left colon sit in the retroperitoneum. To access this space an incision is made along the line of Toldt. The colon is then mobilized from the retroperitoneum. Care is taken to avoid injury to the ureters and duodenum. The surgery then follows the same steps as small bowel resection. However, due to the colon's placement in the retroperitoneum, more dissection is often required to allow for tension free anastomosis.

Small bowel or colon cancer may require surgical resection.

Small bowel cancer often presents late in the course due to non-specific symptoms and has poor survival rates. Risk factors for small bowel cancer include genetically inherited polyposis syndromes, age over sixty years, and history of Crohn's or Celiac disease. Cases that present before stage IV show survival benefit from surgical resection with clear margins. It is recommended that surgical resection also include lymph node sampling of a minimum of 12 nodes with some groups extolling more extensive resection. When evaluation determines cancer to be stage IV, surgical intervention is no longer curative, and is only used for symptom relief.