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
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 large intestine and a small intestine. Your large intestine (colon) connects your small intestine with your rectum (the pouch at the end of your large intestine where stool is stored until you pass it). Small sacs or pouches (diverticula) can develop in your large intestine. They're probably caused by high pressure in the intestine. Having several of these pouches is called diverticulosis Diverticulosis 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... read more .

What is diverticulitis?

Diverticulitis is a complication of diverticulosis. Stool and bacteria get trapped in diverticula, small pouches or sacs that form in the lining of your intestine. The bacteria cause an infection.

  • Symptoms include pain in the lower left part of your belly, tenderness, and fever

  • Doctors find diverticulitis with a CT scan

  • Treatment includes rest, a liquid diet, and antibiotics

  • If you have severe symptoms, you may need a hospital stay and sometimes surgery

Large Intestine with Diverticula

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

Large Intestine with Diverticula

What causes diverticulitis?

Sometimes, stool and bacteria get into one of the sacs (diverticula), causing inflammation and infection.

  • Diverticulitis is usually in the lowermost part of your large intestine

  • Diverticulitis tends to be more serious in older people and in people taking corticosteroids

If you have diverticulosis, you have a higher risk of getting diverticulitis if you:

  • Are older

  • Are overweight

  • Don't exercise

  • Smoke

  • Eat a high-fat, low-fiber diet

  • Take certain medicines, such as corticosteroids, opioid pain medicines, and anti-inflammatory medicines

What are the symptoms of diverticulitis?

Diverticulitis causes:

  • Pain in the lower left part of your belly

  • Tenderness

  • Fever

Diverticulitis can cause problems such as:

Some Complications of Diverticulitis

Some Complications of Diverticulitis

How can doctors tell if I have diverticulitis?

How do doctors treat diverticulitis?

You can treat mild diverticulitis at home with:

  • Rest

  • A special diet—eat only liquids for a few days, such as broth, juice, or water, and then slowly add in soft foods, such as eggs, cooked vegetables, or yogurt

  • Pain medicine

  • Sometimes, antibiotics

If you have more serious symptoms, you may need to stay in the hospital for treatment. Your treatment may involve:

  • Fluids and antibiotics in your vein

  • Pain medicine

  • Bed rest

  • No food until your symptoms stop

  • Sometimes, putting a needle through the skin to drain an infection with a pocket of pus (abscess)

You may need emergency surgery if:

  • Your symptoms don’t improve or get worse

  • You have increasing pain, tenderness, and fever

  • Your intestine is blocked

  • Your intestine bursts, causing an infection in the lining of your belly (peritonitis)

  • You have an abscess that needs to be drained

Your doctor removes the ruptured (burst) part of your intestine. Then your doctor will either reconnect your intestine or give you a temporary colostomy. A colostomy is a surgical opening in your belly connected to one end of your intestine. Stool exits into the colostomy bag while your intestine heals.

A fistula that forms can also be treated with surgery.

Several weeks after you're better, doctors usually do a colonoscopy Endoscopy "Endo" means inside, and "scope" means look. So an endoscope is an instrument doctors use to look inside your body. Endoscopes can also be used to do tests and treat diseases. Endoscopes are... read more (a test in which a doctor inserts a thin, lighted tube with a small camera through your rectum to look at your large intestine) to be sure that your intestine has healed.

Doctors will also tell you to:

  • Eat more fiber

  • Exercise

  • Lose weight if you're overweight

  • Not smoke

It's important to call your doctor if symptoms of diverticulitis happen again.

Others also read
Test your knowledge
Hashimoto Thyroiditis
Hashimoto thyroiditis results when the body attacks the cells of the thyroid gland. This is called an autoimmune reaction. Hashimoto thyroiditis is most common in which of the following populations?
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