Ranitidine injection is used to treat conditions caused by excess stomach acid. It works by blocking histamine receptors in the stomach, reducing acid production. This medication is commonly used in hospital settings for treating peptic ulcers, gastroesophageal reflux disease (GERD), and conditions like Zollinger-Ellison syndrome, where there is overproduction of gastric acid. Ranitidine injection can also be given to patients with upper gastrointestinal bleeding to reduce acid-related damage. Additionally, it is used for preventing aspiration pneumonia in patients undergoing surgery or those in intensive care, particularly when oral intake is not possible. The injection offers a faster method of administration compared to oral tablets.