Troy Francis, a middle-aged salesman, complains of a burning pain in the 'pit of his stomach,' usually beginning about two hours after eating and abating after drinking a glass of milk. When asked to indicate the site, he points to his epigastric region. The GI tract is examined by X-ray fluoroscopy. A gastric ulcer is visualized, and drug therapy using a proton pump inhibitor and antibiotics is recommended. a. Why is this treatment suggested? b. What are the possible consequences of nontreatment?