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Condition Basics

What is diverticulitis?

Diverticulitis is a digestion problem. It happens when pouches (diverticula) form in the wall of the colon and then become inflamed or infected. This can cause tenderness, cramps, or pain in the belly.

Not everyone who has these pouches gets diverticulitis. Mild attacks of diverticulitis may heal on their own. When the infection and symptoms are severe, it may need treatment in a hospital.

What causes it?

Doctors aren't sure what causes diverticulitis. Bacteria grow in pouches (diverticula) that sometimes grow in the wall of the colon. This bacteria can lead to inflammation or infection.

What are the symptoms?

Belly pain, often in the lower left side, is the most common symptom of diverticulitis. The pain is sometimes worse when you move. Other symptoms include fever, chills, bloating, and gas. You may also have diarrhea or constipation. Symptoms can last from a few hours to several days, or longer if not treated.

How is it diagnosed?

To diagnose diverticulitis, your doctor will ask questions about your symptoms and examine you. You may have tests to see if you have an infection or other problems. The tests may include blood tests or a digital rectal exam. They may also include CT scans, ultrasound, or X-rays of your belly, or other tests.

How is diverticulitis treated?

Treatment for mild symptoms of diverticulitis starts with antibiotics, pain medicines, and diet changes. You can try home treatment, such as a heating pad, for pain. To treat serious symptoms, you may need a hospital stay or surgery.


Doctors aren't sure what causes diverticulitis. Bacteria grow in pouches (diverticula) that sometimes grow in the wall of the colon. This bacteria can lead to inflammation or infection.

It is not known why some people who have these diverticula (a condition called diverticulosis) get diverticulitis and others do not.

Doctors think diverticula form when high pressure inside the colon pushes against weak spots in the colon wall. Uncoordinated movements of the colon can also contribute to the development of diverticula.

In most cases, a diet with good fiber makes stool that is bulky and can move easily through the colon. If a diet is low in fiber, the colon must exert more pressure than usual to move small, hard stool. A low-fiber diet also can increase the time stool remains in the bowel. This adds to the high pressure. Pouches may form when the high pressure pushes against weak spots in the colon.

What Increases Your Risk

The possibility of having diverticulitis increases with age.

You may be more likely to develop diverticulitis if you:


You can do some things to help prevent diverticulitis.

  • Eat a high-fiber diet that is low in fat and red meat.

    Whole-grain breads and cereals, brown rice, and fresh fruits and vegetables can all be part of a high-fiber diet.

  • Take a fiber supplement, such as Citrucel or Metamucil, every day if needed.

    Read and follow all instructions on the label.

  • Practice healthy bowel habits.

    You can try eating at regular times, not straining during a bowel movement, and getting plenty of fluids each day.

  • Schedule time each day for a bowel movement.

    Having a daily routine may help.

  • Drink plenty of water.
  • Exercise regularly.

Learn more


Symptoms of diverticulitis may last from a few hours to several days. They may last longer if it's not treated. These symptoms may include:

  • Tenderness, cramps, or pain in the belly. This is often in the lower left side but may occur on the right. These symptoms are sometimes worse when you move. Pain is the most common symptom.
  • Fever and chills.
  • A bloated feeling, swelling in the belly, or gas.
  • Diarrhea or constipation.
  • Nausea and sometimes vomiting.
  • Not feeling like eating.

Complications also can cause symptoms. If an abnormal opening (fistula) develops between the colon and the vagina or the colon and the urethra, you may pass air or stool from the vagina or the urethra.

Other conditions, such as irritable bowel syndrome (IBS) or a urinary tract infection, may cause symptoms similar to diverticulitis.

What Happens

Diverticulitis occurs when pouches (diverticula) that have formed in the wall of the large intestine (colon) become inflamed or infected. It is not known why some people who have these pouches (diverticulosis) develop diverticulitis and others do not.

Mild attacks of diverticulitis, with few symptoms of infection or inflammation, sometimes heal without treatment. In most cases, doctors prescribe oral antibiotics. They may also suggest a clear liquid diet to rest the bowel until it isn't inflamed.

When infection and symptoms are severe, diverticulitis is treated in the hospital. Treatment includes antibiotics given in a vein (IV) and resting the bowel with IV fluids. If symptoms are severe and not treated, problems such as an abscess or fistula may happen. Surgery often is needed to treat these.

It is common to have lower belly pain after recovering from an attack of diverticulitis. But this pain doesn't always mean it's returned.

When to Call

Call 911 or other emergency services immediately if the person has been bleeding from the anus and has signs of shock. This could mean that a diverticular pouch is bleeding (diverticular bleeding). Signs of shock include passing out, or feeling very dizzy, weak, or less alert.

Call your doctor now if you have pain in your belly that is in one spot (as opposed to general pain in the belly), especially if you also have:

  • Fever or chills.
  • Nausea and vomiting.
  • Unusual changes in your bowel movements or swelling in your belly.
  • Blood in your stool.
  • Pain that's worse when you move.
  • Burning pain when you urinate.
  • Abnormal vaginal discharge.

Call your doctor now if you have:

  • Severe pain in your belly that is getting worse.
  • Pain in your belly that gets worse when you move or cough.
  • A stool that is mostly blood (more than a few streaks of blood on the stool). Blood in the stool may appear as reddish or maroon-colored liquid or clots. Or it may produce a black stool that looks like tar.
  • Passed gas or stool from your urethra while urinating. This likely means that you have an opening (fistula) between the bowel and the urinary tract.

Call your doctor if you:

  • Have cramping pain that does not get better when you have a bowel movement or pass gas.
  • Have rectal bleeding.
  • Have a change in bowel habits.
  • Have been losing weight without trying.

Call your doctor if you are treating mild diverticulitis at home and:

  • You have a fever.
  • Your pain is getting worse.
  • You can't keep down liquids.
  • You are not better after 3 days.

Watchful waiting

It can be common to have bloating, gas pressure, or mild belly pain. These can be caused by eating certain foods or by stress. Home treatment usually will take care of these symptoms. If home treatment doesn't help or if the symptoms become worse, see your doctor.

Check your symptoms

Exams and Tests

To diagnose diverticulitis, your doctor will ask questions about your symptoms and examine you. He or she may do tests to see if you have an infection or to make sure that you don't have other problems. Tests may include:

  • Blood tests, such as a complete blood count (CBC). A CBC may show if you have an infection.
  • Other tests, such as an CT scan, ultrasound, MRI, or X-ray of your belly. These may provide clues about the cause of belly pain and other symptoms.
  • A digital rectal exam. This looks for tenderness or a mass in the lower pelvic area.
  • A fecal occult blood test. This looks for blood in your stool.
  • Flexible sigmoidoscopy and colonoscopy. These may be done if you have bleeding or to look for narrow spots or growths in the bowel.

Learn more

Treatment Overview

Treatment depends on how bad your symptoms are. If the pain is mild, you are able to drink liquids, and you have no signs of complications, treatment may include:

  • Medicines such as antibiotics and pain relievers.
  • Changes in diet. These changes start with a clear-liquid or bland diet that is low in fiber. You follow this diet until the pain goes away. You then increase how much fiber you eat.
  • Home treatment. This could include using a heating pad or trying deep breathing.

If the pain is severe, you are not able to drink liquids, or you have complications of diverticulitis, you may need a hospital stay. Treatment will include:

  • Antibiotics given in a vein (intravenous, or IV).
  • Fluids and food given through your vein only (no food or drink by mouth) for up to a week. This allows the bowel to rest.

Sometimes surgery is needed to treat some problems or repeated attacks.


  • Drink plenty of fluids. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.
  • Stay with liquids or a bland diet (plain rice, bananas, dry toast or crackers, applesauce) until you are feeling better. Then you can return to regular foods and slowly increase the amount of fiber in your diet.
  • Use a heating pad set on low on your belly to relieve mild cramps and pain.
  • Get extra rest until you are feeling better.
  • Be safe with medicines. Read and follow all instructions on the label.
    • If the doctor gave you a prescription medicine for pain, take it as prescribed.
    • If you are not taking a prescription pain medicine, ask your doctor if you can take an over-the-counter medicine.
  • If your doctor prescribed antibiotics, take them as directed. Do not stop taking them just because you feel better. You need to take the full course of antibiotics.
  • Do not use laxatives or enemas unless your doctor tells you to use them.

Learn more


Medicines to stop infection and to control symptoms often are used to treat attacks of diverticulitis.

  • Antibiotics are given to treat the infection causing the attack.
  • Prescription pain relievers sometimes are needed if nonprescription pain relievers cannot control the pain.

Medicines are not used to prevent future attacks of diverticulitis.

Learn more


People who have mild, brief attacks and who are willing to try long-term diet changes may be able to avoid surgery. If you have repeated attacks of diverticulitis, you may need surgery.

Surgery, called bowel resection, involves removing the diseased part of the large intestine (partial colectomy) and reconnecting the parts that remain. Depending on the symptoms and how serious they are, more than one surgery may be needed to correct the problem. When more than one surgery is needed, the person most often has a colostomy during the time between surgeries. A colostomy is a procedure in which the upper part of the intestine is sewn to an opening made in the skin of the belly. Stool passes out of the body at this opening and into a disposable bag. In most cases, the colostomy is removed at a later time and the intestine is reconnected.

Overall, fewer than 6 out of 100 people who have diverticulitis need surgery.footnote 2

You may decide to have surgery for diverticulitis if you have:

  • Repeated attacks. Surgery to remove the diseased part of the colon often is suggested if you have two or more severe attacks.
  • A high risk of repeated attacks. (This includes people younger than age 40 or people with an impaired immune system.)
  • An abnormal opening (fistula) that has formed between the colon and an adjacent organ, most often the bladder, uterus, or vagina.

Surgery for diverticulitis may be needed if you have problems, including:

  • An infected pouch (diverticulum) that has ruptured into the abdominal cavity, especially if a pocket of infection (abscess) has formed.
  • An infection that has spread into the abdominal cavity (peritonitis).
  • A blocked colon (bowel obstruction) or a narrow spot in the colon (stricture).
  • Infection that has spread through the blood to other parts of the body (sepsis).
  • Repeated problems with bleeding or severe bleeding that does not stop with other treatments.

In some cases of diverticulitis, a pocket of infection (abscess) in the belly heals on its own. At other times it can be drained without surgery. A needle is passed through the skin into the abscess, and the liquid that is infected is drained. A computed tomography (CT) scan is used to help the doctor guide the needle into the abscess. Sometimes a plastic drain is placed for a time in the belly to drain the abscess.

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  1. Strate LL, et al. (2011). Use of aspirin or nonsteroidal anti-inflammatory drugs increases risk for diverticulitis and diverticular bleeding. Gastroenterology, 140(5): 1427–1433.
  2. Harford WV (2010). Diverticulosis, diverticulitis, and appendicitis. In EG Nabel, ed., ACP Medicine, section 4, chap. 12. Hamilton, ON: BC Decker.


Current as of: February 10, 2021

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Jerome B. Simon MD, FRCPC, FACP - Gastroenterology


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