Treatment with cytotoxic agents involve great risk for patients due to the toxicity of drugs but also human factors. This project explores: 1) if areas of special risk to be considered when prescribing can be identified 2)if these areas can be handled by by a CDSS and if this will lead to better safety for patients 3) effects of such a system on task, system and actors Methods: Action research, videoobservation and interviews, testing of prototypes, meaning condensation and analysis of safety aspects from papers by Nolan, Barber and Reason.