A new WHO guideline provides recommendations for developing balanced national policies on controlled medicines to ensure accessibility, availability, and affordability for medical and scientific purposes while minimizing risks from non-medical use. The guideline addresses medicines essential for pain management, palliative care, mental health, neurological conditions, substance use disorders, and use in humanitarian emergencies. Covering opioids, benzodiazepines, barbiturates, cannabinoids, stimulants, and others, the recommendations highlight the importance of meeting the needs of all age groups, including vulnerable populations, in line with international obligations and the WHO Roadmap for access to medicines.