Nanomedicine promises unprecedented innovations for diagnosis and therapy as well as for predicting and preventing diseases. On the other hand it raises fears linked to new and unknown characteristics of nanoscale materials. Both, promises and fears, are closely linked to the realm of uncertainty. To a large extent it is currently not known which expectations could become reality and which suspected adverse events might come true. Medicine is quite familiar with decision-making under uncertainty. Rules and regulations for clinical research have (...) been developed to reduce possible harm for research participants without abandoning necessary investigations. Here we examine whether clinical research trials of nanomedicine need new regulations and conclude that the established rules should suffice. (shrink)