ATC WHO represents the WHO Anatomical Therapeutic Chemical (ATC) classification system within MyHealth@MyHands. The ATC classification system organises active pharmaceutical substances into groups according to the organ or system on which they act and their therapeutic, pharmacological, and chemical properties. It is the international standard for medication classification in health statistics, pharmacoepidemiology, and ePrescription systems. ATC WHO is mandated for medication coding in EEHRxF-compliant ePrescription and eDispensation exchanges within MyHealth@EU.