Mechanical Bowel Obstruction



The bowel is a muscular tube that is constantly moving to push food through. Blockage may be caused by something blocking the inside of the tube or something that stops the intestine from working well.

Most small bowel blockages are due to scar tissue connecting the bowel to the abdominal wall or other organs. This makes it hard for the bowel to work as needed. Most large bowel obstructions are caused by tumors.

Other causes of bowel obstructions include:

  • Hernia—part of the intestine pokes through abdominal wall and squeezes intestine shut
  • Bowel inflammation or swelling
  • Foreign matter in the intestines
  • Impacted feces—bulk of feces becomes trapped in the rectum
  • Volvulus—twisting of the intestine
  • Intussusception—when the intestine pulls inward into itself (this is the most common cause in children)

Risk Factors

Things that may raise the risk of a bowel obstruction are:

  • Previous gastrointestinal or gynecologic surgery—can lead to scar tissue
  • Diverticulitis
  • Crohn disease
  • Hirschsprung disease—in infants and children
  • Cancer of the gastrointestinal tract



Symptoms of a bowel obstruction include:

  • Belly pain and cramps
  • Abdominal swelling
  • Nausea and vomiting
  • Diarrhea
  • Severe constipation
  • Bloating
  • Fever
  • Bad breath


The doctor will ask about symptoms and past health. A physical exam will be done. A stethoscope will be placed on the abdomen to listen for bowel sounds. If no sounds are heard, it may point to a bowel obstruction.

Pictures of the abdomen will be taken. This can be done with one or more of the following:



The goal of treatment is to remove the blockage and allow food and liquid to pass as it should. How this is done will depend on what is causing the blockage. Options are:

  • Nasogastric tube—a tube is passed through the nose and down into the stomach to remove fluids that have become trapped
  • Removal of fecal impaction—Feces trapped in the rectum can be manually loosened and removed
  • Endoscopy—A thin, lighted tube is inserted through the rectum and into the large intestine to straighten out the intestines
  • Surgery may be needed to:
    • Remove scar tissue, tumors, foreign matter, and other causes of the blockages
    • Repair hernias
    • Remove damaged tissue


Some bowel obstructions cannot be prevented. Taking steps to avoid constipation may help, such as:

  • Eating foods that are high in fiber
  • Drinking plenty of fluids
  • Exercising regularly

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.