The Swiss health system results from a balance between federal and cantonal (state) legislation. Federal laws were instituted to combat infectious disease, certain other severe or widespread diseases, and alcohol and drug abuse; for the protection against harmful agents or substances; and on health and accident insurance. Cantonal implementation permits adaptation to local situations. In the case of health protection, this interplay of federal standards setting and cantonal implementation has been generally successful, but situations in the areas of immunization and breast cancer screening are presented, where, in the absence of uniform legislative guidance, cultural and political diversity has led to regionally different approaches. Varying levels of preventive action have resulted in measurable differences in mortality and morbidity. Lessons for other countries are discussed, where decentralization of preventive and health care services is being considered.