Abstract: An underwater drainage device for removing fluid, blood and gases from the pleural cavity between the lung and the surrounding rib cage of patient. The underwater drainage device includes a collection chamber in fluid communication with the patient, a water seal chamber and a suction chamber. There is a baffled manifold which interconnects and provides fluid communication between the chambers. The collection chamber is removably connected to the manifold to permit emptying and/or testing of the fluid therein. The manometer chamber is also removable to permit changing the amount of suction. There is an anti-flux device which retards liquid flow from the water seal chamber in the event of high negativity at the patient. The device is constructed so that there is minimal fluid loss in the event the device is knocked over and there is a stand and hooks for positioning the underwater drainage device where desired.