Gasec 40 mg is a medication that contains Omeprazole, a proton pump inhibitor (PPI) that reduces stomach acid production. It is primarily used to treat conditions caused by excessive acid in the stomach, such as gastric ulcers, gastroesophageal reflux disease (GERD), Zollinger-Ellison syndrome, and erosive esophagitis. It works by blocking the proton pumps in the stomach lining, thereby lowering acid secretion and allowing ulcers and inflammation to heal