A common ethical code for everybody involved in health care is desirable, but there are important limitations to the role such a code could play. In order to understand these limitations the approach to ethics using principles and their application to medicine is discussed, and in particular the implications of their being prima facie. The expectation of what an ethical code can do changes depending on how ethical properties in general are understood. The difficulties encountered when ethical values are applied (...) reactively to an objective world can be avoided by seeing them as a more integral part of our understanding of the world. It is concluded that an ethical code can establish important values and describe a common ethical context for health care but is of limited use in solving new and complex ethical problems. (shrink)