A dialysis machine comprising: a console connectable to a patient to perform dialysis, the console comprising: a control system having a controller, the control system being configured to carry out a dialysis procedure on the patient, the control system comprising a graphical user interface, the graphical user interface comprising a display and user data entry system (12A, 12B, 12C), the control system being configured to produce a video output to show screens on the display for setting up and controlling dialysis parameters in response to user input commands using the data entry system; a multimedia player, the multimedia player being independent from the control system and being configured to respond to a command signal from the control system to control the playing of a multimedia file to reproduce a video on the display, the multimedia player being configured to select and access the multimedia file from a memory (54, 68, 80); and a switch configured to, responsive to a second command signal from the control system, alternate between supplying the video output from the control system to the display and supplying a second video output from the multimedia player to the display, wherein the control system can take control of the display in event of an emergency and carry out the dialysis procedure without the multimedia player. a console connectable to a patient to perform dialysis, the console comprising: a control system having a controller, the control system being configured to carry out a dialysis procedure on the patient, the control system comprising a graphical user interface, the graphical user interface comprising a display and user data entry system (12A, 12B, 12C), the control system being configured to produce a video output to show screens on the display for setting up and controlling dialysis parameters in response to user input commands using the data entry system; a multimedia player, the multimedia player being independent from the control system and being configured to respond to a command signal from the control system to control the playing of a multimedia file to reproduce a video on the display, the multimedia player being configured to select and access the multimedia file from a memory (54, 68, 80); and a switch configured to, responsive to a second command signal from the control system, alternate between supplying the video output from the control system to the display and supplying a second video output from the multimedia player to the display, a control system having a controller, the control system being configured to carry out a dialysis procedure on the patient, the control system comprising a graphical user interface, the graphical user interface comprising a display and user data entry system (12A, 12B, 12C), the control system being configured to produce a video output to show screens on the display for setting up and controlling dialysis parameters in response to user input commands using the data entry system; a multimedia player, the multimedia player being independent from the control system and being configured to respond to a command signal from the control system to control the playing of a multimedia file to reproduce a video on the display, the multimedia player being configured to select and access the multimedia file from a memory (54, 68, 80); and a switch configured to, responsive to a second command signal from the control system, alternate between supplying the video output from the control system to the display and supplying a second video output from the multimedia player to the display, wherein the control system can take control of the display in event of an emergency and carry out the dialysis procedure without the multimedia player.