Most people with diverticulosis do not have any discomfort or symptoms. Some people may experience cramps or discomfort in the lower left abdomen, bloating, and changes in bowel habits (diarrhoea and constipation). Other conditions such as irritable bowel syndrome, stomach ulcers and colorectal cancer can cause similar symptoms, so these symptoms do not always mean a person only has diverticulosis.
The most common symptom of diverticulitis is abdominal pain. The most common sign on examination is tenderness in the abdomen. The pain is usually severe and comes on suddenly, but it can also be mild and worsening over several days. The intensity of the pain can fluctuate. A person may also experience cramping, nausea, vomiting, fever, and chills.
Some people with diverticulosis may experience sudden and massive bleeding from the rectum. This is usually of a large volume, and will require admission for monitoring and possibly blood transfusions. While more than 90% of patients with this condition will stop bleeding without any intervention, a small number of patients may have a life-threatening bleed that results in heart attacks, strokes or even death.