The invention relates to a system for the extraction and infusion of a body fluid, in particular a system for the extraction and infusion of blood, having a fluid distribution device with an outer structural element at which several connection ports are formed and an inner structural element which is arranged, at least partially, in a seat in the outer structural element, is displaceable between positions and has a hollow space configured for the intake and discharge of a fluid. The invention also relates to a method for operating a system for the extraction and infusion of a body fluid.
