Ranitidine is a prescription drug used to treat ulcers of the stomach and intestines and to prevent intestinal ulcers from coming back after they have healed. Ranitidine is also used to treat certain stomach and throat problems such as erosive esophagitis, gastroesophageal reflux disease or GERD, and Zollinger-Ellison syndrome. It works by decreasing the amount of acid your stomach makes. It relieves symptoms such as cough that doesn’t go away, stomach pain, heartburn, and difficulty swallowing.  Ranitidine belongs to a class of drugs known as H2 blockers.