The invention relates to a device (1), in particular for protecting and for cleaning the bladder lumen, consisting of at least one functional body (2) which can be spatially expanded in a variable manner and can be modified at least partially from a small state into a larger state. Said device (1) protects the bladder lumen from bacterial invasion when the functional body (2) is inserted into the bladder and helps an infected bladder during mechanical cleaning and subsequent healing. The invention also relates to the use of the device (1) for medical, in particular prophylactic and therapeutic purposes.
