[ATC classification: lights and shadows]

The issue draws the story of ATC classification which, risen from the need to study drug consumption in different countries, is extending towards the regulatory area. The features of ATC classification which get it superior to the classification used by different pharmaceutical european data sheet compendia, are the introduction of an anatomical level and study of the criteria used for the definition of levels (ATC guidelines). However some important problems are still open, which suggest great attention in the application of ATC system to regulatory area. Finally, it is underlined the necessity to modify continuously the ATC system on time with the development of scientific acquisition.