by Lucey JR


Small bowel obstruction means the small intestine is partially or totally blocked. When this happens, the contents of the intestine cannot properly get out of the body. Stools, fluid, and gas build up inside the intestine. This is a potentially serious condition that requires urgent medical care.


Bowel obstruction may be caused by a mechanical problem. In this case, something inside the body blocks the movement of material through the intestine.

It can also be caused by ileus , a slowing down or stopping of bowel activity. Ileus is a nonmechanical type of obstruction, which may also be referred to as pseudo-obstruction.

Mechanical small bowel obstruction may be caused by:

  • Adhesions—scar tissue left behind, in most cases by previous abdominal surgery
  • Intussusception —telescoping of the intestinal wall
  • Volvulus—the intestine twists on itself
  • Impacted foreign bodies—items that were swallowed and got stuck

Ileus may be caused by surgery on the intestine or certain medications such as opioids.

Small Bowel Obstruction
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Risk Factors

Factors that may increase your chances of small bowel obstruction include:

  • Hernias
  • Crohn disease —an inflammatory bowel condition
  • Abdominal, joint, or spine surgery
  • Swallowing a foreign body
  • Decreased blood supply to the small bowel
  • Abnormal growth of tissue in or next to the small intestine
  • Tumors in the small intestine
  • Cancer
  • Infection in the lining of the small intestine
  • Kidney disease
  • Long-standing diabetes
  • Rarely, gallstones


Symptoms of small bowel obstruction often occur in combination. Small bowel obstruction may cause:

  • Abdominal fullness and/or excessive gas
  • Distension—abdomen feels stretched out more than normal
  • Pain and cramps in stomach area
  • Vomiting
  • Constipation
  • Diarrhea
  • Bad breath

Ileus pain is often less severe than mechanical small bowel obstruction.


You will be asked about your symptoms and medical history. A physical exam will be done. The exam will include listening for bowel sounds in your stomach. Very high pitched bowel sounds heard through a stethoscope suggest mechanical bowel obstruction. Conversely, ileus often produces no bowel sounds.

Imaging tests are used to evaluate abdominal structures. These may include:


Treatment depends on the cause and severity of the obstruction. You will usually require treatment by a specialist. Your doctor will also treat you for any underlying conditions that contribute to small bowel obstruction.

Initial Care

Before any surgical treatment or procedure can begin, you may need to be stabilized. This may include:

  • Monitoring and IV fluids—Observation at a hospital may be needed to see if the blockage will get better on its own. No food will be allowed and fluids will be given through an IV.
  • Nasogastric tube—A tube is inserted through the nose and into the stomach to remove fluids and gas, which can promptly relieve pain and pressure. It will be left in place until the intestines are working well.
  • Catheterization—A tube is placed in the bladder to drain and test urine.

After the blockage is relieved, nutrition is given through an IV or feeding tube until you are able to eat solid foods. Other treatment for small bowel obstruction includes:


Medications may include:

  • Pain relievers
  • Oral triple therapy—to reduce gas, bloating, and improve symptoms
  • Muscle stimulants—to promote muscle contraction in the intestine
  • Antibiotics—to treat bacterial infections


Surgery may be needed if you do not respond to medical treatment, or in the following circumstances:

  • Intestinal strangulation, which may be caused by volvulus or intussusception
  • Cancer
  • Abdominal adhesions
  • Hernias
  • Peritonitis


There are no current guidelines to prevent small bowel obstruction. Managing any underlying conditions such as Crohn disease, can reduce your chances.


National Cancer Institute 

National Institute of Diabetes and Digestive and Kidney Diseases 


Canadian Association of Gastroenterology 

Crohn's and Colitis Canada 


Abdominal adhesions. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: Updated September 2013. Accessed January 9, 2018.

Baron TH. Acute colonic obstruction. Gastrointest Endosc Clin N Am. 2007;(17)2:323-329.

Bonin EA, Baron TH. Update on the indications and use of colonic stents. Curr Gastroenterol Rep. 2010;12(5):374-382.

Gastrointestinal complications—for health professionals (PDQ). National Cancer Institute website. Available at: Updated May 10, 2017. Accessed January 9, 2018.

Intestinal pseudo-obstruction. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: Updated February 2014. Accessed January 9, 2018.

Kulaylat MN, Doerr RJ. Small bowel obstruction. Available at: Accessed January 9, 2018.

Small bowel obstruction. EBSCO DynaMed Plus website. Available at:  . Updated August 9, 2017. Accessed January 9, 2018.

4/7/2014 DynaMed Plus Systematic Literature Surveillance  : Katz DS, Baker ME, Rosen MP, et al. Suspected small bowel obstruction. American College of Radiology (ACR) Appropriateness Criteria. Available at: Updated 2013.

Revision Information

  • Reviewer: EBSCO Medical Review Board Daus Mahnke, MD
  • Review Date: 11/2018
  • Update Date: 12/20/2014