Zollinger-Ellison syndrome (ZES) is a rare disorder characterized by the development of one or more tumors, known as gastrinomas, in the pancreas or upper part of the small intestine. These gastrinomas secrete excessive amounts of the hormone gastrin, leading to an overproduction of stomach acid, which subsequently causes recurrent peptic ulcers, abdominal pain, and diarrhea. ZES can affect individuals at any stage of life, though it is most commonly diagnosed between the ages of 20 and 60. This article provides an in-depth overview of the causes, symptoms, and diagnostic methods for Zollinger-Ellison syndrome. It also explores the latest treatment options, including acid-reducing medications, surgical tumor removal, and innovative approaches aimed at managing symptoms and improving patient outcomes. Early detection and tailored treatment are critical in minimizing complications associated with ZES and enhancing the quality of life for affected individuals.