CBSE Class 9 Answered

Peptic ulcers are ulcers that form in the stomach or the upper part of the small intestine, called the duodenum. An ulcer in the stomach is called a gastric ulcer and an ulcer in the duodenum is called a duodenal ulcer.

Both a gastric ulcer and a duodenal ulcer result when H. pylori or a drug weakens the protective mucous coating of the stomach and duodenum, allowing acid to get through to the sensitive lining beneath. Both the acid and the bacteria can irritate the lining and cause an ulcer to form.