A purge device for a medical treatment fluids administration system, comprising: - a coupling element intended to be coupled to a distal end portion of a flow tube including a plurality of fluid flow conduits, the coupling element comprising: - a plurality of fluid flow channels, each fluid flow channel comprising a proximal end (12.1) intended to be fluidly connected to a respective fluid flow conduit of the flow tube and a distal end (12.2) opposite to the respective proximal end (12.1), and - a plurality of fluid flow apertures, each fluid flow aperture being fluidly connected to a respective fluid flow channel, - a closure element comprising a fluid evacuation aperture and a closure portion, the closure element being movably mounted relative to the coupling element and being configured to occupy a plurality of closed positions in each of which the closure portion closes off the distal end (12.2) of a fluid flow channel and the fluid evacuation aperture is fluidly connected to the fluid flow aperture which is fluidly connected to the fluid flow channel whose distal end is closed off by the closure portion, characterized in that the closure element includes a hollow body extending along a longitudinal axis and provided with an axial through passage extending over the entire length of the hollow body, the coupling element extending at least partly in the axial through passage, in that the fluid evacuation aperture is provided on the hollow body and opens into the axial through passage, in that the closure element is configured to occupy at least one released position in which the closure portion releases the distal ends (12.2) of the fluid flow channels and the fluid evacuation aperture is fluidly isolated from the fluid flow apertures, and in that the purge device further comprises a connection end fitting intended to be connected to a catheter, the connection end fitting comprising an outlet orifice configured to be fluidly connected to the distal ends (12.2) of the fluid flow channels and intended to be fluidly connected to the catheter. - a coupling element intended to be coupled to a distal end portion of a flow tube including a plurality of fluid flow conduits, the coupling element comprising: - a plurality of fluid flow channels, each fluid flow channel comprising a proximal end (12.1) intended to be fluidly connected to a respective fluid flow conduit of the flow tube and a distal end (12.2) opposite to the respective proximal end (12.1), and - a plurality of fluid flow apertures, each fluid flow aperture being fluidly connected to a respective fluid flow channel, - a plurality of fluid flow channels, each fluid flow channel comprising a proximal end (12.1) intended to be fluidly connected to a respective fluid flow conduit of the flow tube and a distal end (12.2) opposite to the respective proximal end (12.1), and - a plurality of fluid flow apertures, each fluid flow aperture being fluidly connected to a respective fluid flow channel, - a closure element comprising a fluid evacuation aperture and a closure portion, the closure element being movably mounted relative to the coupling element and being configured to occupy a plurality of closed positions in each of which the closure portion closes off the distal end (12.2) of a fluid flow channel and the fluid evacuation aperture is fluidly connected to the fluid flow aperture which is fluidly connected to the fluid flow channel whose distal end is closed off by the closure portion,