A pyothorax is a relatively rare occurrence in a general hospital and is posing a number of problems. Among these the long mean duration of hospitalisation is of note lasting 47 days for 24 patients at our clinic. The course and the mortality rate are influenced by early detection and judicious use of interdisciplinary treatment. Small effusions accompanying pneumonia are frequent and likely to disappear after treatment of the underlying disease. In these instances a precipitate punction may lead to secondary infection. In case of a sterile punctate the pH value and consideration of glucose and LDH values determine further measures. Computed tomography is of great value since it yields decisive information not available from conventional radiography. If the empyema is not segregated in compartments a closed drainage with a large caliber chest-tube ist the method of choice. Limited thoracotomy is advised when several empyema chambers develop after short duration of the illness. Persistent disease or widespread scarring necessitate decortication in most cases.