A device for thoracic drainage comprises a container connector for a secretion collection container (3), which can be connected to the pleural cavity of a patient, and a venting device (10) for releasing air from the secretion collection container in passive operation. In order to keep the counterpressure as low as possible during the air release and thus make it easier to force air out of the pleural cavity (1) of a patient, the venting device has a controllable vent valve (12). For this purpose, a control device (7) determines the pressure in the secretion collection container by reading out a pressure sensor (11) and controls the valve to release air from the secretion collection container when the determined pressure exceeds a threshold value. The device can optionally also be operated actively by way of a vacuum connector (25). An ancillary line (2′) permits monitoring of the drainage line (2).