Lansoprazole is a proton-pump inhibitor (PPI) which inhibits the stomach's production of gastric acids.Lansoprazole is manufactured by a number of companies worldwide under several brand names. Lansoprazole is a proton-pump inhibitor (PPI) in the same pharmacologic class as omeprazole.Lansoprazole has been marketed for many years and is one of several PPIs available.Lansoprazole is a racemate 1:1-mixture of the enantiomers dexlansoprazole and levolansoprazole.

1. Treatment of ulcers of the stomach and duodenum, and NSAID-induced ulcers.

2. Adjunctive treatment of Helicobacter pylori infection, alongside antibiotics. Treatment to kill Helicobacter pylori (H. pylori) causing ulcers or other problems involves using two other drugs besides lansoprazole. This treatment is known as "triple therapy", and involves taking twice daily for 10 or 14 days lansoprazole 30 mg, amoxicillin 1,000 mg, and clarithromycin 500 mg.

3. Treatment of gastroesophageal reflux disease (GERD) (also known as acid reflux disease).

4. Treatment of Zollinger-Ellison Syndrome.