This image shows what can happen when an ulcer injures the stomach. On the left is the normal pylorus, which is the channel through which food and liquid exit the stomach into the duodenum, the first portion of the small bowel. On the right is a second exit caused by a previous ulcer that burst through into the duodenum. If it had perforated into the abdomen, it would have caused acute peritonitis, a surgical emergency. You can see that the ulcer disease is still active with a new white-based ulcer in the distance. The previous and present ulcers were caused by the stomach bacteria infection called Helicobacter pylori. Antibiotics cleared the infection and cured the ulcer problem.