High-dose chemotherapy with autologous and allogeneic blood stem cell transplantation has become a standard therapy for hematological malignancies and solid tumors. To ensure quality of treatment and adherence to internationally approved protocols, the use of computer systems has been introduced in some oncology centers. Most software packages cannot be used automatically by other institutions because of different treatment strategies and medications. To overcome this problem, we designed a software system based on an Oracle database, which allows the user to develop his own therapy blocks and assemble them to generate specific therapy plans. The system supports the daily work of the physicians by suggesting medications based on changes in the vital parameters or the clinical chemistry. Parameters can be given upper and lower limits whose surpassing leads to treatment suggestions by the system. All quantitative variables may be depicted in a graphical way. The system is connected to external laboratory devices. Export of data to international registries is possible. Until now, 43 patients have been transplanted with the help of this system. There is a high degree of acceptance among the nursing staff and the physicians. The system can be transferred to other centers, if the local hardware and network capacities meet the minimal requirements.