Diverticulosis is more common in older adults, affecting up to 10 percent of Americans over age 40 and 50 percent of people over age 60; 10 to 25 percent of people with diverticulosis will develop diverticulitis, according to MedlinePlus. Diverticulitis is a serious condition that causes pain in the lower left abdomen that is usually sudden and severe. It may also be accompanied by fever, nausea, vomiting, chills and cramping. The goal of treatment is to clear up the infection and reduce inflammation. Depending on how severe your symptoms are, you may be in the hospital on intravenous fluids or you may be resting at home and consuming a clear liquid diet.