Most patients with diverticulosis have no symptoms. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), less than 10 percent of diverticulosis patients experience symptoms. The location, size or number of diverticula does not seem to have any effect on the presence or severity of symptoms.

Patients with diverticulosis do not usually have a fever, an elevated white blood cell count or other signs of infection, which may indicate diverticulitis. Some patients with diverticulosis may experience various symptoms, including:

• Noticeable muscle spasms. Some patients may feel localized (occurring in a specific area) muscle spasms, usually on the lower left side of the abdomen.
  
  
• Pain. Some patients feel mild, crampy, localized pain or tenderness, typically in the lower left side of the abdomen. The pain generally comes and goes and may be made worse by eating. Bowel movements or flatulence may make the pain go away.
  
  
• Bloating or feelings of fullness. Patients may feel bloated or full. The abdomen, particularly on the lower left side, may feel full or tense to the touch.
  
  
• Constipation, diarrhea or flatulence. The stool of some patients may be abnormally hard or soft. Constipation is somewhat more common than diarrhea in people with diverticulosis. Some patients may pass a greater amount of gas.
  
  
• Intestinal bleeding. In rare cases, small arteries that are often located beside the diverticula may rupture, causing bleeding. This appears to occur more often near pouches on the right side of the colon (which is rare in the United States but more common in some Asian countries). Diverticular bleeding is generally sudden and painless. It results in noticeable amounts of bright red to maroon blood in the stool. This bleeding generally stops on its own, does not recur and requires no treatment. In the rare cases where it does not stop or recurs, treatment, possibly surgery to remove the diverticula, may be necessary.