An Overview of Diverticular Disease

Diverticular disease is an umbrella term that refers to the condition where outpouchings (called diverticula) are present in the wall of the colon, and any symptoms or complications that may occur as a result. Having diverticula, which is called diverticulosis, is more common in people over the age of 40, and occurs in more than half all people over the age of 60.

In most cases the diverticula cause no symptoms but in a minority of cases they can become inflamed and cause a condition called diverticulitis. Diverticulitis can cause abdominal pain, fever, and bleeding. Complications can include the development of an abscess, fistula, blockages, or colon perforation, but this is not common.

Diverticulitis used to be thought of as common, but recent research shows that it occurs in only about 5% of people who have diverticula in their colon.

Large Intestine Anatomy

Understanding the anatomy of the large and small intestine can help when discussing diverticulitis with a physician. The large intestine is an organ that includes the colon, the rectum, and the anal canal. The colon begins at the end of the small intestine, is about six feet long, and has four sections: the ascending colon, transverse colon, descending colon, and sigmoid colon. The rectum is where stool is stored until it’s passed out of the anus as a bowel movement.


Diverticula usually don’t cause any symptoms. That’s why most people won’t know that they have them unless they’re found during a colonoscopy.

However, symptoms such as abdominal pain and fever can begin when the diverticula become inflamed (which is diverticulitis). Complications may occur in some cases, which can lead to rectal bleeding and significant pain. These symptoms could indicate a medical emergency (such as an infection or a bowel obstruction) and medical attention should be sought right away. Blood in the stool is never normal, even if it has happened before, and is always a reason to see a physician.

Diverticulitis symptoms


It's not well understood why diverticula develop, though there are some theories. As people age, the wall of the colon may develop weak points, causing the outpouchings to form, which are the diverticulum. Diverticula occur most often in the sigmoid colon, which is the last section of the colon and is attached to the rectum.

Previously, the working theory was that a lack of dietary fiber was a major contributor to the development of diverticular disease. However, it’s now thought that diverticular disease may have more to do with genetics, though this is still not well understood. Another theory is that high pressure within the colon could cause the bulges to form.

Diverticulitis (which is what the condition is called when the diverticula cause symptoms) may be a result of a buildup of stool or unhealthy bacteria in a diverticula. It’s not currently thought that there is a way to prevent the development of either diverticula or diverticulitis. However, it’s thought that there are some factors that may contribute to diverticulitis:


In most cases, diverticula don’t cause symptoms and won’t therefore be found and diagnosed. Although diverticula might be first discovered during a screening colonoscopy for colorectal cancer (which is recommended for healthy adults who have no other risk factors between ages 45 and 50).

When there are symptoms such as abdominal pain or bleeding, a gastroenterologist might decide to see what’s going on inside the colon by doing one or more tests, which can include a colonoscopy or a computed tomography (CT) scan.

A colonoscopy is a test where a tube with a camera and a light on the end is inserted in through the anus in order to see the inside of the colon. A CT scan is a type of X-ray that is noninvasive and might be given with or without the use of contrast dye, which is usually given both orally and through an IV in order to better see what’s going on inside the body.


Treatment isn't needed for diverticula that are not causing any symptoms. However, a physician may recommend a high fiber diet that includes plenty of fruits and vegetables. For diverticulitis, treatment is with antibiotics, which in most cases can be taken at home, but in some situations are given intravenously in a hospital. If there are complications, such as an abscess, fistula, stricture, blockage, or a perforation (hole) in the colon, other treatments might be needed. 

Surgery could be used to treat a complication, or if the diverticulitis becomes recurrent, in which case it’s better to remove the part of the bowel that is affected. Surgery might include a resection to remove part of the bowel or ostomy surgery (ileostomy or colostomy) where a stoma is created and waste is collected on an appliance worn on the abdomen.

A Word From Verywell

Many people, especially those over the age of 50, have diverticula in their colon but don’t experience any symptoms. The understanding of what causes the diverticula to become inflamed has changed in recent years. It used to be thought that people with diverticula needed to avoid certain foods such as seeds, nuts, and popcorn, because those foods could get “stuck” in one of the pouches.

It’s no longer thought that people need to change their diet if they have diverticula. Every person with diverticular disease will need to determine the diet that works best for them to avoid symptoms.

For the small percentage of people with diverticula who develop diverticulitis, treatment is usually with oral antibiotics, but in the case of severe symptoms, hospitalization might be needed. Severe disease or complications might require surgery, but this is not common. Most people will recover well with the conservative management of the diverticulitis (which includes bowel rest and antibiotics) and the prognosis is good.

Eating a well-balanced diet with enough fiber and getting physical activity are lifestyle changes that may help people who have diverticular disease to avoid complications from the condition.

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  • Shahedi K, Fuller G, Bolus R, et al. "Long-term risk of acute diverticulitis among patients with incidental diverticulosis found during colonoscopy." Clinical Gastroenterology and Hepatology. 2013;11(12):1609–1613. doi: 10.1016/j.cgh.2013.06.020.
  • Strate LL, Liu YL, Aldoori WH, Giovannucci EL. "Physical activity decreases diverticular complications.” Am J Gastroenterol. 2009 May;104(5):1221-30. doi: 10.1038/ajg.2009.121.
  • Strate LL, Liu YL, Huang ES, Giovannucci EL, Chan AT. "Use of aspirin or nonsteroidal anti-inflammatory drugs increases risk for diverticulitis and diverticular bleeding.” Gastroenterology. 2011 May;140:1427-1433. doi: 10.1053/j.gastro.2011.02.004.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.