Intravenous infusion of hydrochloric acid was used as a safe, effective, and quantitative method for correction of metabolic alkalosis in two patients. The first shows the risks of intravenously administered ammonium chloride, the currently available alternative to hydrochloric acid therapy. The second shows the efficacy of intravenously administered hydrochloric acid. While breathing spontaneously throughout the period of severe alkalosis, this patient showed compensatory hypoventilation with conspicuous increase in arterial carbon dioxide pressure. Normal spontaneous ventilation returned with correction of the metabolic alkalosis.