If you are like one out of every ten Americans, you may suffer from the burning, gnawing pain caused by a peptic ulcer. Peptic ulcers are sores, or breaks in the lining of the stomach. Many people think that peptic ulcers are caused by stress, excessive gastric acid, or diet, however medical research has yet to bear this out. If it is not stress, excess stomach acid, or what you eat, what really does cause peptic ulcers?