Decision support, order entry, drug and care administration with their respective documentation cannot be seen as independent actions, especially in term of medical approach and patient safety. Chemotherapy treatment is a good example to illustrate the various implication of technology information in these multifaceted and intricate processes. Chemotherapy administration can be a highly complex process. It can take place over a variable period of time, from hours to months. Chemotherapies can be produced specifically for a given patient and can have dramatic effects in case of errors. Chemotherapy treatment will depend from various information including patient specific data such as temperature, weight or laboratory or drug specific knowledge such as side effects or administration directives. At the University Hospitals of Geneva (HUG), processes reengineering accompanied with new applications covering the whole chain of the processes involved in chemotherapy treatment (prescription preparation, administration, control) have been developed. This paper presents the overall approach leading the computerization of these processes and the first evaluations about the potential benefits of the computer-aided controls during the administration phase.