Heartburn is a burning feeling in your chest caused by stomach acids traveling back up towards your throat and mouth (acid reflux). It happens because a muscle above your stomach relaxes too much and allows stomach contents and acid to come back up into your esophagus and mouth. This can be a symptom of indigestion (dyspepsia). Ranitec 150 Tablet belongs to a group of medicines called histamine 2 antagonists. It works by reducing the amount of acid your stomach makes and relieves the pain associated with heartburn and indigestion.