Acid-base status was determined in 86 patients with cirrhosis of the liver. Group I comprised 55 patients living more than 3 months after examination (stable). Another 18 stable patients with a surgical porta-caval shunt (p.c.a.) formed group II. Group III consisted of 12 terminal patients without p.c.a. examined within the last week of life. With respect to liver function group II was intermediate between I and III. The most common acid-base disturbance in group I was compensated respiratory alkalosis (20%) followed by compensated metabolic alkalosis (15%). 50% of group II presented compensated respiratory alkalosis. 85% of group III showed metabolic acidosis, which was compensated in only half of the patients. Respiratory alkalosis seemed more related to impairment of liver function than to portasystemic shunting. The genesis of the terminal metabolic acidosis was complex. Renal function was reduced in 92% of group III, and lactic acidosis was found in 36%. In this group hepatic function was most severely impaired, and 60% were hypotensive. These disturbances were not related to aetiology or treatment of the liver disease.