Some people develop small pouches (diverticula) that bulge outward through weak spots in the colon. Diverticulosis is the condition of having these pouches; diverticulitis is an inflammation or infection in these pouches. The conditions diverticulosis and diverticulitis are both referred to as diverticular disease. Diverticulosis may not cause any symptoms but could include mild cramps, bloating and constipation – all of which are common to other conditions such as IBS or ulcers. The most common symptoms of diverticulitis are abdominal pain and tenderness around the left side of the lower abdomen. When infection is the cause, fever, nausea, vomiting, chills, cramping and constipation may also occur.