The disturbance of miction after general surgical operations has three causes. They exist individually and combined. The first cause is a relative trauma of anaesthesiological remedies. They have a central site of action in the brain stem and a peripheral one in the parasympathetic and sympathetic ganglian of the urinary bladder. The second cause is an operative trauma of the abdomino-pelvic initial reflex of the miction. The two traumata, the vegetative and the mechanical one, decompensate an imminent neuropathic or obstructive reduction of the urinary bladder. The two traumata are prolonged by abdominal, pulmonary and cerebral insufficiency. The third cause is a direct lesion of the sacral plexus pelvicus. - The postoperative disturbance of miction concerns about 25% of all operated persons. Children are specifically rarely concerned. Operations on the lower half of the body cause the disturbance of miction by far more frequently than operations on the upper half of the body or on extremities. The therapy consists of a rational, liberal and differentiated use of the catheter, further in parasympathomimetic and sympatholytic medication, in the obstructively or neuropathically decompensated cases in transurethral operative correction of the outlet of the urinary bladder.