Background: Conventional proton pump inhibitors (PPIs) are the main first-line therapy to treat acid-related disorders (1). However, they have a number of limitations including slow onset of action, influence by cytochrome P450 polymorphisms, unsatisfactory effects at night, and instability in acidic conditions (1). Potassium-competitive acid blockers (P-CABs) induce a rapid, long-lasting, and reversible inhibition of the gastric hydrogen potassium ATPase, the proton pump of the stomach (1). These agents have a faster onset of action than PPIs, and they have a more sustained action in inhibiting acid secretion. Thus, they represent a new option to treat acid-related disorders. Herby we summarize the mechanism of action of PCABs.