IE 10 or 11 may display this page improperly. Please upgrade to Microsoft Edge, Google Chrome, or Firefox.

What Is a Proton Pump Inhibitor (PPI)?

Learn about what PPIs are and how they work to treat frequent heartburn.

Proton pump inhibitors (PPIs) are medications used to reduce the production of stomach acid in order to treat frequent heartburn, defined as heartburn occurring two or more days per week. Unlike antacids, PPIs treat frequent heartburn at the source*. Prilosec OTC, for example, uses the PPI ingredient omeprazole, so you don’t get heartburn in the first place*.

How PPIs work 

PPIs bind to proton pumps in the stomach and stop them from producing as much acid as they normally would. They bind to the specific enzymes in your stomach lining that trigger acid production, which reduces the overall amount of acid your body produces. PPIs don’t just treat the symptoms of heartburn; they treat heartburn at the source.

Comparisons of heartburn treatments 

Antacids neutralize acid in your stomach to provide fast but short-term (1-3 hours) relief.

Acid controllers stop some of the pumps that produce acid in the stomach, partially reducing stomach acid, but only providing daylong (8-12 hours) relief.

PPIs, like acid controllers, also reduce your body’s ability to make stomach acid. However, PPIs provide all-day and all-night (24 hours) relief and treat frequent heartburn at the source with one pill each day, which is why they are specifically indicated to treat frequent heartburn.


There are many over-the-counter (OTC) PPIs. Common OTC PPIs include esomeprazole, lansoprazole and omeprazole, which is the active ingredient in Prilosec OTC.

If you have frequent heartburn, talk to your doctor about taking a PPI, like Prilosec OTC.

*It’s possible while taking Prilosec OTC®. Use as directed for 14 days to treat frequent heartburn. Do not take for more than 14 days or more often than once every four months unless directed by a doctor. May take 1-4 days for full effect.