Omeprazole is one of the proton pump inhibitors (PPI) applied to decrease the production of stomach acid; therefore, being effective in the treatment of conditions such as gastroesophageal reflux disease (GERD), peptic ulcers and Zollinger- Ellison syndrome. The mechanism of action is to block the enzyme on the stomach lining which secretes acids hence relieving some heartburn, acid reflux and promoting ulcer healing.