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FAQs : The Anatomical Therapeutic Chemical (ATC) classification system

Anatomical Therapeutic Chemical (ATC)

In the ATC classification drugs are divided into different groups according to the organ or system in which they act and their chemical, pharmacological and therapeutic properties. The Anatomical Therapeutic Chemical (ATC) classification is maintained by the WHO Collaborating Centre for Drug Statistics Methodology in Oslo, Norway. The ATC classification is an integrated part of the WHO Drug Dictionaries.

  • Anatomical is the organ or system on which a drug acts.
  • Therapeutic (and Pharmacological) is Indication for typical use(s)
  • Chemical is the Compound structure and properties.

ATC Levels

The ATC classification hierarchical levels:

  1. 14 anatomical groups designated by the letters A - V.
  2. Therapeutic main groups.
  3. Therapeutic/pharmacological subdivision which is designated by letters.
  4. Therapeutic/pharmacological/chemical subgroup which is designated by letters. In the 4th level the pharmacological properties and the chemical nature of the substance are taken into account.
  5. Individual substance designated by numbers. This level is not used in the WHO Drug Dictionaries.
For more information about the ATC classification please contact the WHO Collaborating Centre for Drug Statistics Methodology

FAQ on The Anatomical Therapeutic Chemical (ATC) classification system last updated on 1 September 2010