This document discusses essential medicine lists and concepts. It defines essential medicines as drugs that satisfy the priority healthcare needs of a population according to the World Health Organization. Essential medicines should be available at all times in adequate amounts and appropriate dosage forms within functioning health systems. They also need to provide adequate information and be affordable. The document notes the World Health Organization's 19th essential medicines list from 2015 and Nepal's 4th national essential medicines list from 2011, which includes 368 medicines and is modified for different healthcare facility levels.