Final answer:
Proton pump inhibitors are used to treat Gastroesophageal reflux disease (GERD), Peptic ulcer disease (PUD), and Zollinger-Ellison syndrome but not Irritable bowel syndrome (IBS).
Step-by-step explanation:
Proton pump inhibitors (PPIs) are a class of medications that reduce the production of stomach acid and are used to treat various acid-related conditions.
However, they are not used for treating Irritable bowel syndrome (IBS), which is a gastrointestinal disorder characterized by a combination of symptoms including abdominal pain and changes in bowel habits. Conditions that are treated with PPIs include Gastroesophageal reflux disease (GERD), where acid from the stomach causes heartburn and injury to the esophagus; Peptic ulcer disease (PUD), often associated with Helicobacter pylori infections or certain medications, which creates ulcers in the stomach lining; and Zollinger-Ellison syndrome, a rare condition leading to excessive acid production.