The efficacy and safety of bioactive compounds depend on a few known and unknown parameters. What is a physiologic dose and how can that dose be defined in cases of bioactive compounds with a poor knowledge of supply and distribution? What safety sets are needed? How can individual aspects such as polymorphisms or differences in absorption be considered? A group of experts tried to answer these and related questions during the 23rd Hohenheim Consensus Meeting at the University of Hohenheim in Stuttgart.