Final answer:
A peptic ulcer is a sore in the lining of the stomach or the duodenum caused by H. pylori infection or excessive NSAID intake. It can be diagnosed based on symptoms or the presence of H. pylori and can be treated with antibiotics and stomach acid reducing medications.
Step-by-step explanation:
A peptic ulcer is a sore in the lining of the stomach or the duodenum. It can be caused by infection with the bacterium Helicobacter pylori or excessive intake of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin. The ulcer can be painful due to irritation of the ulcerated tissue by acidic gastric juice. Peptic ulcers are usually diagnosed based on symptoms or the presence of H. pylori in the gastrointestinal tract, and can be treated with antibiotics to kill H. pylori and medications to decrease stomach acid and aid in healing.