Cimetidine is an oral medication belonging to the class of histamine H2 receptor antagonists. It is commonly used to treat conditions related to excess stomach acid production, such as acid reflux, gastroesophageal reflux disease (GERD), peptic ulcers, and Zollinger-Ellison syndrome.

Cimetidine works by blocking the action of histamine on specific receptors in the stomach lining, which helps reduce the production of stomach acid. By decreasing acid secretion, the medication can alleviate symptoms like heartburn, indigestion, and stomach pain associated with conditions where excessive acid causes discomfort.

This medication is available in various forms, including tablets and oral suspensions, allowing for flexible dosing options to suit individual patient needs. Cimetidine is typically taken orally, and the dosage may vary depending on the specific condition being treated and the patient's medical history.