Proton pump inhibitors (PPIs) are used to treat several conditions that affect the digestive system. These include:

• Gastroesophageal reflux disease (GERD). A condition in which acidic food or liquid from the stomach backs up into the esophagus, which connects the mouth to the stomach. PPIs are considered to be the most effective medication for treating GERD.
  
  
• Peptic ulcers. Sores that develop in the lining of the stomach or duodenum, the first part of the small intestine. PPIs do not kill Helicobacter pylori, the bacterium that causes peptic ulcers. For this reason, antibiotics may also be used to treat peptic ulcers.
  
  
• Gastritis. Inflammation of the stomach lining. PPIs are used when the condition is severe enough to require the strongest medication available.
  
  
• Indigestion. A burning feeling or discomfort in the upper abdomen caused by many different factors, including diseases such as GERD and ulcers, as well as lifestyle activities such as eating too much or eating high-fat foods.
  
  
• Zollinger-Ellison syndrome. Rare condition that causes tumors to form in the pancreas and duodenum, or ulcers to form in the stomach or duodenum. PPIs are considered to be the most effective drug for treating this condition, and are used to both reduce production of stomach acid and to promote healing.