The essential medicines list (EML) is a fundamental pillar in promoting the rational use of medicines, grounded in the principle of the “right to health.” Essential medicines are those that should be consistently available in sufficient quantities, in appropriate dosage forms, with guaranteed quality, and at a cost that is affordable to both individuals and communities across all levels of the healthcare system. The main aim of the WHO’s efforts to promote rational medicine use is to ensure that both healthcare providers and patients use medicines in a clinically appropriate and cost-effective manner. Access to essential medicines remains uneven, especially in low- and middle-income countries (LMICs), where healthcare equity is still a significant challenge. Improving the rational use of medicines is crucial for reducing morbidity and mortality, while also helping to contain healthcare costs. Addressing these gaps requires a multidisciplinary and collaborative approach, involving stakeholders from across the healthcare spectrum. Efforts must focus on strengthening existing health infrastructure, enhancing workforce capacity, and implementing evidence-based policies that promote universal access to essential medicines and support the effective application of rational drug use at all levels of care.