The invention relates to a catheter (20), in particular a balloon catheter,having a fluid-carrying element(2), such as a drainage tube, with an inner lumen (2g) for carrying away bodyfluid, and having anexpansion element, such as a balloon (1) of variable cross section, for fixingthe catheter in a bodycavity. The fluid-carrying element (2) has a wall portion (2c) of an open-porematerial (3), which is influidic communication with the inner lumen (2g) and through which the bodyfluid can be aspiratedinto the inner lumen (2g) by applying a negative pressure to a proximal end ofthe fluid-carryingelement (2). The invention furthermore relates to a catheter system having acatheter of the inventionand to a vacuum-generating system connected to the catheter.
