The effects of a single dose of nifedipine (20 mg sublingually) on hemodynamics and tissue oxygenation were evaluated in 24 patients suffering from pulmonary hypertension secondary to severe chronic obstructive lung disease. A significant improvement in pulmonary circulation and right ventricular pump function occurred. An increase in the oxygen delivery to the tissue was also demonstrated. A complementary study in 10 patients showed that the effects observed after a single dose were still apparent after oral intake (30 mg/day) for 15 days. For these reasons nifedipine may contribute in the treatment of cor pulmonale.