Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link
Quick Facts



The Manual's Editorial Staff

Last full review/revision Jan 2020| Content last modified Jan 2020
Click here for the Professional Version
Get the full details
Topic Resources

Your intestine is the long tube in your digestive system that digests food and absorbs nutrients. You have a small intestine and a large intestine. Your large intestine (colon) connects your small intestine to your rectum (the pouch at the end of your large intestine where stool is stored until you pass it).

What is diverticulosis?

In diverticulosis, several tiny sacs or pouches form in your large intestine. These sacs are called diverticula.

  • Diverticulosis is common as people get older, and by age 90 most people have diverticulosis

  • Diverticulosis usually causes no symptoms unless one of the diverticula bleeds

  • Diverticulitis is a similar-sounding condition in which one of your diverticula gets inflamed and painful

  • Doctors find diverticulosis when they do a colonoscopy or x-ray to look for other problems

  • Eating a high-fiber diet may prevent more sacs from forming

Large Intestine with Diverticula

Diverticula are balloon-like sacs that can develop in the large intestine.

Large Intestine with Diverticula

What causes diverticulosis?

Diverticulosis is probably caused by high pressure in your intestine. A low-fiber diet may cause the increased pressure. The increased pressure causes weak spots in your intestine’s wall to bulge, creating a sac or pouch.

Diverticulosis usually happens after age 40. It gets more common as you get older. Almost all people who reach age 90 have diverticulosis.

What are the symptoms of diverticulosis?

Most people with diverticulosis don't have symptoms except sometimes people feel:

  • Constipated

  • Cramping belly pain

  • Bloated

Otherwise, you're unlikely to have symptoms unless you develop complications such as diverticulitis or bleeding.

Sometimes, one of the sacs bleeds, causing blood in your stool. The bleeding usually stops on its own, but it can be heavy.

How can doctors tell if I have diverticulosis?

Doctors find diverticulosis when they do tests for other reasons, such as belly pain or bleeding. Diverticulosis can show up on the following tests:

How do doctors treat diverticulosis?

Doctors don't treat diverticulosis itself, but they may try to prevent its complications by lessening the pressure in your intestine. They'll have you:

  • Eat a high-fiber diet (lots of vegetables, fruits, and whole grains)

  • Drink plenty of fluids

  • Sometimes, eat bran or take supplements to bulk up your stool

Most bleeding stops without treatment. If it doesn't, doctors often do a colonoscopy to:

  • Close the bleeding area with heat or a laser

  • Inject the area with medicine

If colonoscopy treatments don't stop the bleeding, doctors may do angiography. In angiography, they thread a small tube through one of your blood vessels into the bleeding spot. Then they inject substances that block off the bleeding blood vessel. People rarely need surgery to stop the bleeding.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version


Others also read

Test your knowledge

Abortion is defined as the intentional ending of a pregnancy by surgery or drugs. Which of the following statements about abortion in the United States is most accurate? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID