Ranitidine is used to treat ulcers in the stomach. It belongs to a group of drugs called histamine-2 blockers. By blocking the action of histamine on stomach cells, Ranitidine reduces stomach acid production and thus prevents heartburn and stomach pain. This medicine is also used to treat Zollinger–Ellison syndrome and gastroesophageal reflux disease (GERD). This medicine may also be used to treat other conditions as determined by your doctor.