Acid‐related disorders are prevalent in many countries. Research over the last century into the physiology of gastric acid secretion has yielded valuable insight into pathophysiology of many of these disorders. The discovery that histamine, gastrin, and acetylcholine all effect the production of gastric acid paved the way for the development of the H2RAs and PPIs. These agents have subsequently revolutionized the treatment of many acid‐related disorders in clinical practice.