International language for drug utilization research

The Anatomical Therapeutic Chemical (ATC) classification system and the Defined Daily Dose (DDD) as a measuring unit have become the gold standard for international drug utilization monitoring and research.

The ATC/DDD system is a tool for exchanging and comparing data on drug use at international, national or local levels.

Welcome to the WHO Collaborating Centre for Drug Statistics Methodology 

The WHO Collaborating Centre for Drug Statistics Methodology will be closed between 9 July and 6 August 2021 due to summer holidays.