In a patient with viral pneumonia, acute respiratory and renal failure and metabolic acidosis, a reduction in left ventricular stroke work was observed on the three occasions that 100 ml of 8.4% sodium bicarbonate was infused. Blood pressure and cardiac output decreased on two of the occasions. Since intravenous sodium bicarbonate may produce adverse cardiovascular effects, a right heart catheter should be inserted to monitor these effects when alkali therapy is administered to an acutely ill patient with metabolic acidosis.