Zantac relieves stomach acidity, treats peptic ulcers, bleeding in the stomach and duodenum, and treats heartburn at its source. It reduces stomach acid production for up to 12 hours. Zantac has been used to treat and prevent ulcers in the stomach and intestines. It has also been used to treat conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome.
Zantac has also been used to treat gastroesophageal reflux disease and other conditions in which acid refluxes from the stomach into the esophagus, causing heartburn.