Abstract: The subject matter of the invention is a medical mattress comprising a flexible tubular envelope (1) open at two ends, divided into a central section (3a, 3b) open at both ends and flanked, on either side, by an area forming a border (4a, 4b; 5a, 5b) open at both ends, with two sets of foam elements (8) being insertable in the border sections (4a, 4b; 5a, 5b) and two small water mattresses (7a, 7b) being insertable in the central section (3a, 3b). The elements (7a, 7b, 8) are arranged substantially symmetrical to the transversal center line (T) of the envelope, while the edges (15) facing the water mattresses (7a, 7b) have a concavity forming a central basin (16). An opening (17) formed in the upper wall (1a) of the envelope (1), in the central portion of said basin (16), is connected to one at least flexible tube for discharging body waste and soiled fluids. A device (14) is provided for supplying water to one and/or the other of the two water mattresses (7a, 7b) at a regulated temperature and rate/pressure.