The design and development of information technology for use in health services presents a complex and sensitive situation. It includes not only managing differing interests and situations, but does so in a context that might give rise to negative emotions among the participating users. When the future users are children, this design process becomes even more complex. Participatory design is considered suitable for design with children. The premise for the participation of the children in this study was that they were, or had been treated for cancer. Therefore, their participation could awaken negative emotions, and make the situation difficult for them to handle. How participatory design with children can be conducted in such a sensitive context is therefore explored, grounded in the experience from six design workshops. The workshops evolved around the concept of comics as a way to allow the children to express themselves with familiar means. Three main lessons were learned from the workshops: working in pairs promotes an efficient work situation and the possibility to keep an eye on the children's wellbeing; proxies need to be distanced from the participating children; and the scenarios in the comics set the level of realism of the result. Copyright 2013 ACM.