Abstract
A patient with Laennec''s cirrhosis of the liver and longstanding ascites suddenly developed a large pleural effusion. Evidence of a peritoneo-pleural fistula was obtained by demonstration of the rapid passage of dye from the ascites into the pleural effusion and by the induction of a hydropneumothorax by the intraabdominal installation of O2. The incidence and pathogenesis of pleural effusion in cirrhosis of the liver is briefly discussed.