Abstract: Described is a method and device for conserving organs, body extremities and pieces of body tissue by means of an extracorporal circulation system. Conservation is carried out at room temperature or body temperature. Long-term conservation is carried out using three discrete circulation systems, the first supplying the organs, extremities or pieces of tissue with an aqueous physiological nutrient concentrate or with blood or with a blood product. The oxygen is physically dissolved and supplied through a dialysis membrane by the second circulation system, metabolite exchange and detoxication also taking place at this membrane. The third circulation system cuts in automatically, under timer control, to flush out the tissue. During flushing, circulation system (1) and (2) are switched off in order to avoid the liquids mixing with each other. The various elements of the device are connected up by means of disposable tubing or tubing made of sterilizable material.