Bowel obstruction

Bowel obstruction is when the small intestine or colon is partly or completely blocked. The blockage prevents food, fluids and gas from passing through the intestines normally. The small intestine is the long, tube-shaped organ in the abdomen that receives partially digested food from the stomach and passes digested food to the large intestine. The colon is the longest part of the large intestine. It absorbs water and nutrients from almost completely digested food from the small intestine and passes waste (stool or feces) to the rectum.

Bowel obstruction may also be called intestinal obstruction or malignant bowel obstruction.


Bowel obstruction can be caused by:

  • tumours that block the intestines
  • scar tissue or adhesions (bands of scar tissue that bind tissue together) that form after surgery to the small or large intestines
  • damage to the intestine from radiation therapy
  • certain medicines that affect the digestive tract, such as narcotics, antidiarrheal drugs or some chemotherapy drugs
  • fecal impaction, which is when a large mass of dry, hard stool builds up in the rectum due to chronic constipation

Different types of cancer can cause bowel obstructions, including stomach, colorectal, small intestine, uterine, prostate, bladder and ovarian cancers. Cancers that spread to the abdomen and advanced cancers that press against the colon and small intestine as they grow can also cause bowel obstruction.


Symptoms of bowel obstruction can vary depending on its cause and other factors. Symptoms of bowel obstruction include:

  • abdominal pain
  • abdominal cramps
  • swelling, or distension, of the abdomen
  • nausea
  • vomiting
  • dry mouth
  • constipation
  • diarrhea (loose stool may seep past solid fecal matter in the colon)
  • not being able to have a bowel movement
  • not being able to pass gas, or flatus
  • bad breath
  • fever

Bowel obstruction can lead to a hole, or perforation, in the small intestine or colon. This is called a perforated bowel. It can allow the contents to leak into the peritoneal cavity. This can lead to infection, which is called peritonitis.

Report symptoms to your doctor or healthcare team as soon as possible.


Your doctor will try to find the cause of bowel obstruction. This may include asking questions about your symptoms, bowel patterns, medicines and treatments. Your doctor will also do a physical exam, including feeling the abdomen, listening for bowel sounds and a digital rectal examination (DRE) to check for fecal impaction.

You may need to have the following tests or procedures:

  • abdominal x-ray
  • CT scan
  • upper GI series
  • barium enema
  • colonoscopy

Find out more about these tests and procedures.

Managing bowel obstruction

Once the cause of bowel obstruction is known, your healthcare team can suggest ways to treat it. Treatment options may include a combination of measures, including the following.

Resting the bowel

Your healthcare team may suggest resting the bowel for a few days. This means not taking in liquids or food by mouth. You will be given intravenous (IV) fluids to keep you hydrated and keep your electrolytes balanced. Electrolytes are responsible for the movement of nutrients and wastes into and out of cells to keep body fluids balanced. They also allow muscles to function properly.

Relieve pressure in the abdomen

The healthcare team may use a nasogastric (NG) tube to help relieve abdominal swelling and vomiting. The NG tube is passed through the nose, down the throat and into the stomach. An NG tube can be used to remove the contents of the stomach.

A tube can also be passed through the rectum into the colon to help relieve pressure from a buildup of fluid and gas.


You may be given IV antibiotics to prevent or treat peritonitis that can be caused when the contents of the bowel leaks into the peritoneal cavity. The healthcare team may also prescribe medicines to help relieve pain and nausea.


If the obstruction can’t be managed in other ways, you may need surgery to treat it.

The surgeon may use an endoscope to place an expandable metal stent. An endoscope is a flexible tube with a light and lens. A stent is a mesh-like tube. The stent is used to open up the blockage and keep the bowel open. It can also be used to bypass the blockage so that food can move more easily through the intestines.

A gastrostomy is a surgical procedure to create a stoma, or artificial opening, into the stomach through the abdominal wall. A gastrostomy tube can be passed through the stoma into the stomach. The tube can be used to relieve a buildup of fluid and air in the stomach. It can also be used to deliver medicines and liquids directly to the stomach. A drainage bag with a valve may be attached to the tube. When the valve is open, food drains into the bag, not the intestine. This allows soft food and liquid to be taken by mouth without causing any discomfort.

In some cases, the surgeon may need to take out part of the intestine to relieve a blockage or remove dead tissue. After removing the blockage or dead tissue, the surgeon joins each end of the healthy sections of the intestine. Joining the 2 ends of the intestine is called anastomosis. It creates a new pathway or bypass. Depending on where the blockage is and how much intestine is removed, you may have a colostomy or ileostomy. A colostomy is a surgical procedure to create an opening from the colon to the outside of the body through the abdominal wall. An ileostomy creates an opening from the ileum, or the last part of the small intestine, to the outside of the body through the abdominal wall.

Expert review and references

  • Blocked intestine or gastrointestinal obstruction. American Society of Clinical Oncology (ASCO). Cancer.Net. Alexandria, VA.: American Society of Clinical Oncology (ASCO); 2012.
  • Ansari P . Intestinal obstruction. Beers, M. H., & Berkow, R., (Eds.). Merck Manual for Healthcare Professionals. Rahway, NJ: Merck Research Laboratories; 2012.
  • Longstreth GF . Intestinal obstruction. PubMed Health. U.S. National Library of Medicine; 2012.
  • Ripamonti CI, Gerdes H, Easson AM . Bowel obstruction. Berger AM, Shuster JL Jr, & Von Roenn JH (eds.). Principles and Practice of Palliative Care and Supportive Oncology. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2013: 15: pp. 193-209.

Medical disclaimer

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