A Proton Pump Inhibitor (PPI) is a type of medication that reduces the production of stomach acid. It works by blocking the proton pump in the stomach lining, which is responsible for secreting acid. PPIs are commonly used to treat conditions like gastroesophageal reflux disease (GERD), stomach ulcers, and other acid-related disorders. These medications are available both over-the-counter and by prescription. Common examples of PPIs include omeprazole, lansoprazole, and esomeprazole. While generally effective, long-term use of PPIs may be associated with certain risks, such as nutrient deficiencies and increased susceptibility to infections. Always consult a healthcare provider for guidance.