National

Institute of

Diabetes and

Digestive 

and Kidney

Diseases

NATIONAL 

INSTITUTES

OF HEALTH

National Digestive Diseases Information Clearinghouse

U.S. Department

of Health and

Human Services

Diverticulosis 

and Diverticulitis

What are diverticulosis and 

diverticulitis?

Many people have small pouches in their 

colons that bulge outward through weak 

spots, like an inner tube that pokes through 

weak places in a tire. Each pouch is called a 

diverticulum. Pouches (plural) are called 

diverticula. The condition of having diver

ticula is called diverticulosis. About 10 percent of Americans over the age of 40 have 

diverticulosis. The condition becomes more 

common as people age. About half of all 

people over the age of 60 have diverticulosis.

When the pouches become infected or 

infl amed, the condition is called diverticulitis. 

This happens in 10 to 25 percent of people 

with diverticulosis. Diverticulosis and diverticulitis are also called diverticular disease.

What are the symptoms?

Diverticulosis

Most people with diverticulosis do not have 

any discomfort or symptoms. However, 

symptoms may include mild cramps, bloating, 

and constipation. Other diseases such as 

irritable bowel syndrome (IBS) and stomach 

ulcers cause similar problems, so these 

symptoms do not always mean a person has 

diverticulosis. You should visit your doctor 

if you have these troubling symptoms.

Diverticulitis

The most common symptom of diverticulitis 

is abdominal pain. The most common sign is 

tenderness around the left side of the lower 

abdomen. If infection is the cause, fever, 

nausea, vomiting, chills, cramping, and 

constipation may occur as well. The severity 

of symptoms depends on the extent of the 

infection and complications.

What are the complications?

Diverticulitis can lead to bleeding, infections, 

perforations or tears, or blockages. These 

complications always require treatment to 

prevent them from progressing and causing 

serious illness.

Bleeding

Bleeding from diverticula is a rare complication. When diverticula bleed, blood may 

appear in the toilet or in your stool. Bleeding 

can be severe, but it may stop by itself and not 

require treatment. Doctors believe bleeding 

diverticula are caused by a small blood vessel 

in a diverticulum that weakens and fi nally 

Colon (large intestine)

Diverticula
2 Diverticulosis and Diverticulitis

bursts. If you have bleeding from the rectum, 

you should see your doctor. If the bleeding 

does not stop, surgery may be necessary. 

Abscess, Perforation, 

and Peritonitis

The infection causing diverticulitis often 

clears up after a few days of treatment with 

antibiotics. If the condition gets worse, an 

abscess may form in the colon.

An abscess is an infected area with pus that 

may cause swelling and destroy tissue. Sometimes the infected diverticula may develop 

small holes, called perforations. These perforations allow pus to leak out of the colon 

into the abdominal area. If the abscess is 

small and remains in the colon, it may clear 

up after treatment with antibiotics. If the 

abscess does not clear up with antibiotics, 

the doctor may need to drain it.

To drain the abscess, the doctor uses a 

needle and a small tube called a catheter. 

The doctor inserts the needle through the 

skin and drains the fl uid through the catheter. 

This procedure is called percutaneous catheter drainage. Sometimes surgery is needed 

to clean the abscess and, if necessary, remove 

part of the colon.

A large abscess can become a serious problem 

if the infection leaks out and contaminates 

areas outside the colon. Infection that 

spreads into the abdominal cavity is called 

peritonitis. Peritonitis requires immediate 

surgery to clean the abdominal cavity and 

remove the damaged part of the colon. 

Without surgery, peritonitis can be fatal.

Fistula

A fi stula is an abnormal connection of tissue 

between two organs or between an organ and 

the skin. When damaged tissues come into 

contact with each other during infection, they 

sometimes stick together. If they heal that 

way, a fi stula forms. When diverticulitisrelated infection spreads outside the colon, 

the colon’s tissue may stick to nearby tissues. 

The organs usually involved are the bladder, 

small intestine, and skin.

The most common type of fi stula occurs 

between the bladder and the colon. It affects 

men more than women. This type of fi stula 

can result in a severe, long-lasting infection 

of the urinary tract. The problem can be 

corrected with surgery to remove the fi stula 

and the affected part of the colon.

Intestinal Obstruction

The scarring caused by infection may cause 

partial or total blockage of the large intestine. 

When this happens, the colon is unable 

to move bowel contents normally. When 

the obstruction totally blocks the intestine, 

emergency surgery is necessary. Partial 

blockage is not an emergency, so the surgery 

to correct it can be planned.

What causes diverticular 

disease?

Although not proven, the dominant theory 

is that a low-fi ber diet is the main cause of 

diverticular disease. The disease was fi rst 

noticed in the United States in the early 

1900s. At about the same time, processed 

foods were introduced into the American 

diet. Many processed foods contain refi ned, 

low-fi ber fl our. Unlike whole-wheat fl our, 

refi ned fl our has no wheat bran.

Diverticular disease is common in developed 

or industrialized countries—particularly the 

United States, England, and Australia—

where low-fi ber diets are common. The 

disease is rare in countries of Asia and Africa, 

where people eat high-fi ber vegetable diets.

Fiber is the part of fruits, vegetables, and 

grains that the body cannot digest. Some 

fi ber dissolves easily in water (soluble fi ber). 

It takes on a soft, jelly-like texture in the 

intestines. Some fi ber passes almost 

unchanged through the intestines (insoluble 

fi ber). Both kinds of fi ber help make stools 

soft and easy to pass. Fiber also prevents 

constipation.

Constipation makes the muscles strain to 

move stool that is too hard. It is the main 

cause of increased pressure in the colon. This 

excess pressure might cause the weak spots in 

the colon to bulge out and become diverticula.
3 Diverticulosis and Diverticulitis

When taking a medical history, the doctor 

may ask about bowel habits, symptoms, pain, 

diet, and medications. The physical exam 

usually involves a digital rectal exam. To 

perform this test, the doctor inserts a gloved, 

lubricated fi nger into the rectum to detect 

tenderness, blockage, or blood. The doctor 

may check stool for signs of bleeding and test 

blood for signs of infection. The doctor may 

also order x rays or other tests.

What is the treatment 

for diverticular disease?

 A high-fi ber diet and, occasionally, mild pain 

medications will help relieve symptoms in 

most cases. Sometimes an attack of diverticulitis is serious enough to require a hospital 

stay and possibly surgery.

Diverticulosis

Increasing the amount of fi ber in the diet 

may reduce symptoms of diverticulosis and 

prevent complications such as diverticulitis. 

Fiber keeps stool soft and lowers pressure 

inside the colon so that bowel contents can 

move through easily. The American Dietetic 

Association recommends 20 to 35 grams of 

fi ber each day. The table shows the amount 

of fi ber in some foods that you can easily add 

to your diet.

The doctor may also recommend taking a 

fi ber product such as Citrucel or Metamucil 

once a day. These products are mixed with 

water and provide about 2 to 3.5 grams of 

fi ber per tablespoon, mixed with 8 ounces 

of water.

Avoidance of nuts, popcorn, and sunfl ower, 

pumpkin, caraway, and sesame seeds has 

been recommended by physicians out of fear 

that food particles could enter, block, or 

irritate the diverticula. However, no scientifi c 

data support this treatment measure. Eating a high-fi ber diet is the only requirement 

highly emphasized across the literature and 

eliminating specifi c foods is not necessary. 

The seeds in tomatoes, zucchini, cucumbers, 

strawberries, and raspberries, as well as 

poppy seeds, are generally considered harmless. People differ in the amounts and types 

of foods they can eat. Decisions about diet 

should be made based on what works best for 

each person. Keeping a food diary may help 

identify individual items in one’s diet.

If cramps, bloating, and constipation are 

problems, the doctor may prescribe a short 

course of pain medication. However, many 

medications affect emptying of the colon, 

an undesirable side effect for people with 

diverticulosis.

Diverticulitis occurs when diverticula become 

infected or infl amed. Doctors are not certain 

what causes the infection. It may begin when 

stool or bacteria are caught in the diverticula. 

An attack of diverticulitis can develop 

suddenly and without warning. 

How does the doctor 

diagnose diverticular 

disease?

To diagnose diverticular disease, the doctor 

asks about medical history, does a physical 

exam, and may perform one or more diagnostic tests. Because most people do not 

have symptoms, diverticulosis is often found 

through tests ordered for another ailment.

The doctor will ask about medical history.
4 Diverticulosis and Diverticulitis

Source: United States Department of Agriculture (USDA). USDA Nutrient Database 

for Standard Reference Release 15. Available at www.nal.usda.gov/fnic/cgi-bin/

nut_search.pl. Accessed April 5, 2004.

Amount of Fiber in Some Foods

Fruits

Apple, raw, with skin 1 medium = 3.3 grams

Peach, raw 1 medium = 1.5 grams

Pear, raw 1 medium = 5.1 grams

Tangerine, raw 1 medium = 1.9 grams

Vegetables

Asparagus, fresh, cooked 4 spears = 1.2 grams

Broccoli, fresh, cooked 1/2 cup = 2.6 grams

Brussels sprouts, fresh, cooked 1/2 cup = 2 grams

Cabbage, fresh, cooked 1/2 cup = 1.5 grams

Carrot, fresh, cooked 1/2 cup = 2.3 grams

Caulifl ower, fresh, cooked 1/2 cup = 1.7 grams

Romaine lettuce 1 cup = 1.2 grams

Spinach, fresh, cooked 1/2 cup = 2.2 grams

Summer squash, cooked 1 cup = 2.5 grams

Tomato, raw 1 = 1 gram

Winter squash, cooked 1 cup = 5.7 grams

Starchy Vegetables

Baked beans, canned, plain 1/2 cup = 6.3 grams

Kidney beans, fresh, cooked 1/2 cup = 5.7 grams

Lima beans, fresh, cooked 1/2 cup = 6.6 grams

Potato, fresh, cooked 1 = 2.3 grams

Grains

Bread, whole-wheat 1 slice = 1.9 grams

Brown rice, cooked 1 cup = 3.5 grams

Cereal, bran fl ake 3/4 cup = 5.3 grams

Oatmeal, plain, cooked 3/4 cup = 3 grams

White rice, cooked 1 cup = 0.6 gram
5 Diverticulosis and Diverticulitis

Diverticulitis

Treatment for diverticulitis focuses on clearing up the infection and infl ammation, resting 

the colon, and preventing or minimizing complications. An attack of diverticulitis without 

complications may respond to antibiotics 

within a few days if treated early. 

To help the colon rest, the doctor may recommend bed rest and a liquid diet, along with a 

pain reliever. 

An acute attack with severe pain or severe 

infection may require a hospital stay. Most 

acute cases of diverticulitis are treated with 

antibiotics and a liquid diet. The antibiotics 

are given by injection into a vein. In some 

cases, however, surgery may be necessary.

When is surgery necessary?

If attacks are severe or frequent, the doctor 

may advise surgery. The surgeon removes 

the affected part of the colon and joins the 

remaining sections. This type of surgery, 

called colon resection, aims to keep attacks 

from coming back and to prevent complications. The doctor may also recommend 

surgery for complications of a fi stula or 

intestinal obstruction.

If antibiotics do not correct an attack, 

emergency surgery may be required. Other 

reasons for emergency surgery include a large 

abscess, perforation, peritonitis, or continued 

bleeding.

Emergency surgery usually involves two 

operations. The fi rst surgery will clear the 

infected abdominal cavity and remove part of 

the colon. Because of infection and sometimes obstruction, it is not safe to rejoin the 

colon during the fi rst operation. Instead, the 

surgeon creates a temporary hole, or stoma, 

in the abdomen. The end of the colon is 

connected to the hole, a procedure called a 

colostomy, to allow normal eating and bowel 

movements. The stool goes into a bag 

attached to the opening in the abdomen. In 

the second operation, the surgeon rejoins the 

ends of the colon.

Points to Remember

• Diverticulosis occurs when small 

pouches, called diverticula, bulge 

outward through weak spots in the 

colon (large intestine).

• The pouches form when pressure 

inside the colon builds, usually 

because of constipation.

• Most people with diverticulosis 

never have any discomfort or 

symptoms.

• The most likely cause of 

diverticulosis is a low-fi ber diet 

because it increases constipation 

and pressure inside the colon.

• For most people with diverticulosis, 

eating a high-fi ber diet is the only 

treatment needed.

• You can increase your fi ber intake 

by eating these foods: whole 

grain breads and cereals; fruit like 

apples and peaches; vegetables like 

broccoli, cabbage, spinach, carrots, 

asparagus, and squash; and starchy 

vegetables like kidney beans and 

lima beans.

• Diverticulitis occurs when the 

pouches become infected or 

infl amed and cause pain and 

tenderness around the left side 

of the lower abdomen.
National Digestive Diseases 

Information Clearinghouse

2 Information Way

Bethesda, MD 20892–3570

Phone: 1–800–891–5389

Fax: 703–738–4929

Email: nddic@info.niddk.nih.gov

Internet: www.digestive.niddk.nih.gov

The National Digestive Diseases Information Clearinghouse (NDDIC) is a service 

of the National Institute of Diabetes and 

Digestive and Kidney Diseases (NIDDK). 

The NIDDK is part of the National Institutes of Health of the U.S. Department of 

Health and Human Services. Established 

in 1980, the Clearinghouse provides information about digestive diseases to people 

with digestive disorders and to their families, 

health care professionals, and the public. 

The NDDIC answers inquiries, develops and 

distributes publications, and works closely 

with professional and patient organizations 

and Government agencies to coordinate 

resources about digestive diseases.

Publications produced by the Clearinghouse 

are carefully reviewed by both NIDDK 

scientists and outside experts.

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES

National Institutes of Health

This publication is not copyrighted. The 

Clearinghouse encourages users of this 

fact sheet to duplicate and distribute as 

many copies as desired. 

This fact sheet is also available at 

www.digestive.niddk.nih.gov.

Additional Readings

Diverticular disease. In: Corman ML, 

Allison SI, Kuehne JP. Handbook of Colon 

and Rectal Surgery. Hagerstown, MD; 

2002:637-653.

Diverticular disease. In: King JE, ed. 

Mayo Clinic on Digestive Health. Rochester, 

MN: Mayo Clinic; 2000:125-132.

Marcello PW. Understanding diverticular 

disease. Ostomy Quarterly. 2002;39(2):

56-57.

For More Information

International Foundation for Functional 

Gastrointestinal Disorders 

P.O. Box 170864

Milwaukee, WI 53217–8076

Phone: 1–888–964–2001 or 414–964–1799

Fax: 414–964–7176

Email: iffgd@iffgd.org

Internet: www.iffgd.org

NIH Publication No. 07–1163

October 2006

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Trade, proprietary, or company names appearing 

in this document are used only because they are 

considered necessary in the context of the information provided. If a product is not mentioned, 

the omission does not mean or imply that the 

product is un satisfactory.