Systemic mastocytosis (SM) is a rare disease with abnormal proliferation and infiltration of mast cells in the skin, bone marrow, and viscera including the mucosal surfaces of the digestive tract. Gastrointestinal (GI) symptoms occur in 14%-85% of patients with systemic mastocytosis. The GI symptoms may be as frequent as the better known pruritus, urticaria pigmentosa, and flushing. In fact most recent studies show that the GI symptoms are especially important clinically due to the severity and chronicity of the effects that they produce. GI symptoms may include abdominal pain, diarrhea, nausea, vomiting, and bloating. A case of predominantly GI systemic mastocytosis with unique endoscopic images and pathologic confirmation is herein presented, as well as a current review of the GI manifestations of this disease including endoscopic appearances. Issues such as treatment and prognosis will not be discussed for the purposes of this paper.