Collectively both these ulcers are called peptic ulcers. Like most wounds, if left untreated, ulcers can cause complications, especially if they start bleeding. People have usually managed their ulcers by taking medicines for a long time and avoided foods that upset their stomach. The reason for this breakthrough is because we now know what actually causes peptic ulcers. In the past we thought factors such as stress, excess alcohol or coffee, eating too much spicy or fatty foods or producing too much stomach acid caused peptic ulcers.
Some medicines can also cause a small number of ulcers.
The bacteria H. pylori are very common and are able to live well in the very acid environment of our stomach. Most people pick up these bacteria during childhood, but only a small number of people actually develop ulcers from them later in their life. Ulcers are more common in adults than in children. H. pylori bacteria release chemicals that wear away the lining of your gut, causing ulcers. Since the discovery of these bacteria, various treatments have been developed to kill it.