A catheter has a member that can be inserted into a persons rectum, the member including a first rear opening that communicates with a first passage for discharging bodily fluids from an aperture at the front end of the insertable member. The insertable member includes an expandable ring element communicating with a second rear opening for connection to an inflation device. The catheter includes a probe disposed at the front end of a connection pipe, which pipe is housed in the first passage and connected at the rear end thereof to a device for supplying a pressurized liquid. The probe includes several holes in the rear portion thereof for projecting the liquid backwards, cleaning the colon and pushing the probe forwards.
