THIS article reviews the clinical pharmacology of histamine₂-receptor antagonist drugs (H₂ blockers) and their usefulness in the treatment and prevention of acid-peptic disorders — namely, peptic ulcer disease, Zollinger—Ellison syndrome, gastroesophageal reflux disease, and acute stress ulcers and erosions. Erosive gastritis and erosive duodenitis are often considered acid-peptic diseases, but because they overlap with peptic ulcer disease they are not considered as separate entities in this review. Non-ulcer dyspepsia is not included as an acid-peptic disorder since it does not appear to respond to therapy with H₂ blockers or antacids.¹ H₂ blockers are quite effective . . .