Liver diseases are frequently associated with pulmonary complications and acid-base disorders, alterations which are frequently overlooked and thus undiagnosed in these patients. Among the respiratory abnormalities, mention should be made of the numerous functional and anatomic alterations responsible for arterial desaturation, the frequent chronic hyperventilation and the rare plexiform pulmonary hypertension. Acid-base disorders, especially respiratory alkalosis and metabolic alkalosis, are common. These conditions have a number of therapeutic implications since some of them play an important role in the pathophysiology of hepatic encephalopathy. The complications and their specific diagnostic features are reviewed and some therapeutic proposals are made.