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Symptoms and Signs of Diverticulitis (Diverticulosis)

Doctor's Notes on Diverticulitis and Diverticulosis Diet, Symptoms, Causes, and Treatment

Diverticulitis is inflammation of the small outpouchings, known as diverticuli, in the wall of the large intestine (colon). Diverticulosis refers to the presence of having diverticuli, and diverticulitis is the condition in which these diverticuli become irritated or inflamed. Diverticulosis increases with age due to a weakening of the walls of the colon over time. Increased pressure within the colon, such as with constipation, also promotes the formation of diverticuli. Once diverticulosis is present, it often becomes inflamed and progresses to diverticulitis.

Signs and symptoms associated with diverticulitis include pain in the left lower abdomen, nausea, vomiting, constipation, fever, and sometimes diarrhea or frequent urination. Other signs and symptoms can include rectal bleeding and tenderness in the left lower abdomen.

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Medically Reviewed on 3/11/2019

Diverticulitis and Diverticulosis Diet, Symptoms, Causes, and Treatment Symptoms

Most people with diverticulosis have no symptoms. When symptoms do occur, they are usually mild and include:

  • Pain in the belly (abdomen)
  • Bloating
  • Constipation (less often, diarrhea)
  • Cramping

These symptoms are nonspecific. This means that similar symptoms are seen in many different digestive disorders. They do not necessarily mean that a person has diverticulosis. If an individual has these symptoms, he or she should see a health-care professional.

Diverticulitis is a more serious condition and causes symptoms in most people with the condition that include:

  • Pain in the abdomen, usually in the lower left side
  • Bleeding, bright red or maroon blood may appear in the stool, in the toilet (a symptom of rectal bleeding), or on the toilet paper. Bleeding is often mild and usually stops by itself; however, it can become severe.
  • Fever
  • Nausea
  • Vomiting
  • Chills
  • Constipation (less often, diarrhea)

If diverticulitis is not treated promptly it can develop some very serious complications. A complication is suggested by any of these symptoms:

  • Worsening abdominal pain
  • Persistent fever
  • Vomiting (no food or liquid can be tolerated)
  • Constipation for an extended period of time
  • Burning or pain during urination
  • Bleeding from the rectum

As mentioned previously, eat a diet high in fiber, drink plenty of fluids, and exercise regularly to keep the bowels functioning properly and prevent constipation.

Diverticulitis and Diverticulosis Diet, Symptoms, Causes, and Treatment Causes

Diverticulosis is thought to be caused by increased pressure on the intestinal wall from inside the intestine.

  • As the body ages, the outer layer of the intestinal wall thickens. This causes the open space inside the intestine to narrow. Stool (feces) moves more slowly through the colon, increasing the pressure.
  • Hard stools, such as those produced by a diet low in fiber or slower stool "transit time" through the colon can further increase the pressure.
  • Frequent, repeated straining during bowel movements also increases the pressure and contributes to the formation of diverticula.

Diverticulosis in developed countries is blamed largely on a diet low in fiber.

  • Fiber is found in fruits and vegetables, whole grains, and legumes (beans, peas, and lentils).
  • There are two types of fiber; soluble (dissolves in water) and insoluble.
    • Soluble fiber forms a soft gel-like substance in the digestive tract.
    • Insoluble fiber passes through the digestive tract nearly unchanged.
  • Both are necessary to in the diet keep stool soft and moving easily through the digestive tract.
  • This is how fiber prevents constipation.

Diverticulitis (Diverticulosis) Symptoms, Diet, Treatment Slideshow

Diverticulitis (Diverticulosis) Symptoms, Diet, Treatment Slideshow

A diverticulum is a bulging pouch or sac that can form on internal organs. In this slide show we will discuss colonic diverticula, which are bulging sacs that push outward on the colon wall. Diverticula can occur anywhere in the colon, but most commonly form near the end of the colon on the left side (sigmoid colon).


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.