Without the WHO-DD, a safety signal from a small clinic in Thailand might never be connected to a similar case in Brazil. With it, the global health community can speak one common language: the language of coded, comparable drug data.

| Feature | WHO Drug Dictionary | MedDRA | RxNorm | | :--- | :--- | :--- | :--- | | | Drugs (medicinal products) | Medical conditions / adverse events | Clinical drugs (US-centric) | | Primary Use | Coding drug names & ATC classes | Coding adverse reactions & diagnoses | EHR interoperability in the US | | Global? | Yes (truly international) | Yes (but maintained by ICH) | No (only US drugs) |

In the world of clinical research, pharmacovigilance, and public health, data consistency is critical. With thousands of drug names, manufacturers, and regulatory standards across different countries, how does the global health community ensure that a "paracetamol" in London is the same as an "acetaminophen" in New York? The answer lies in the WHO Drug Dictionary . What is the WHO Drug Dictionary? The WHO Drug Dictionary (WHO-DD) is an international, validated classification system for pharmaceutical substances. Managed by the Uppsala Monitoring Centre (UMC) on behalf of the World Health Organization (WHO), it is the most widely used drug reference database for safety and efficacy studies.