Ischemic colitis occurs when blood flow to part of the large intestine (colon) is temporarily reduced, usually due to constriction of the blood vessels supplying the colon or lower flow of blood through the vessels due to low pressures. The diminished blood flow doesn't provide enough oxygen for the cells in your digestive system, which can result in tissue damage to the affected area of intestine.

Any part of the colon can be affected, but ischemic colitis most commonly causes pain on the left side of the belly area (abdomen).

Ischemic colitis can be misdiagnosed because it can easily be confused with other digestive problems. You may need medication to treat ischemic colitis or prevent infection, or you may need surgery if your colon has been damaged. Most often, however, ischemic colitis heals on its own.


Signs and symptoms of ischemic colitis can include:

  • Pain, tenderness or cramping in your belly, which can occur suddenly or gradually
  • Bright red or maroon blood in your stool or, at times, passage of blood alone without stool
  • A feeling of urgency to move your bowels
  • Diarrhea
  • Nausea

The risk of severe complications is higher when you have symptoms on the right side of your abdomen. This is less commonly seen compared with left-sided colitis. People with right-sided colitis tend to have more underlying medical problems, such as high blood pressure, atrial fibrillation and kidney disease. They more frequently have to undergo surgery and also have a higher mortality risk.

When to see a doctor

Seek immediate medical care if you have sudden, severe abdominal pain. Abdominal pain that makes you so uncomfortable that you can't sit still or find a comfortable position is a medical emergency.

Contact your doctor if you develop worrisome signs and symptoms, such as bloody diarrhea. Early diagnosis and treatment can help prevent serious complications.


The precise cause of diminished blood flow to the colon isn't always clear. But several factors can increase your risk of ischemic colitis:

  • Buildup of fatty deposits on the walls of an artery (atherosclerosis)
  • Low blood pressure (hypotension) associated with dehydration, heart failure, surgery, trauma or shock
  • Bowel obstruction caused by a hernia, scar tissue or a tumor
  • Surgery involving the heart or blood vessels, or the digestive or gynecological systems
  • Other medical disorders that affect your blood, such as inflammation of the blood vessels (vasculitis), lupus or sickle cell anemia
  • Cocaine or methamphetamine use
  • Colon cancer (rare)

The role of medications

The use of certain medicines also can lead to ischemic colitis, though this is rare. These medications include:

  • Some heart and migraine medications
  • Hormone medications, such as estrogen
  • Antibiotics
  • Pseudoephedrine
  • Opioids
  • Certain medications for irritable bowel syndrome
  • Chemotherapy medications

Risk factors

Risk factors for ischemic colitis include:

  • Age. The condition occurs mostly frequently in adults older than age 60. Ischemic colitis that occurs in a young adult may be a sign of a blood-clotting abnormality or inflammation of the blood vessels (vasculitis).
  • Sex. Ischemic colitis is more common in women.
  • Clotting abnormalities. Conditions that affect the way the blood clots, such as factor V Leiden, may increase the risk of ischemic colitis.
  • High cholesterol, which can lead to atherosclerosis.
  • Reduced blood flow, due to heart failure, low blood pressure, shock or certain conditions, such as diabetes or rheumatoid arthritis.
  • Previous abdominal surgery. Scar tissue that forms after surgery may cause reduced blood flow.
  • Heavy exercise, such as marathon running, which can lead to reduced blood flow to the colon.
  • Surgery involving the large artery (aorta) that pumps blood from your heart to the rest of your body.


Ischemic colitis usually gets better on its own within two to three days. In more-severe cases, complications can include:

  • Tissue death (gangrene) resulting from diminished blood flow
  • Hole formation (perforation) in your intestine or persistent bleeding
  • Bowel obstruction (ischemic stricture)


Since the cause of ischemic colitis isn't always clear, there's no certain way to prevent the disorder. Most people who have ischemic colitis recover quickly and may never have another episode.

To prevent recurrent episodes of ischemic colitis, some doctors recommend eliminating any medication that might cause the condition. Making sure to stay adequately hydrated, especially when doing vigorous outdoor activities, is also important — especially for those living in warm climates. A test for clotting abnormalities may be recommended as well, especially if no other cause for ischemic colitis is apparent.

Nov. 10, 2020
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