The WHO Model List of Essential Medicines, published by the World Health Organization, contains the medications considered to be most effective and safe to meet the most important needs in a health system. The list is frequently used by countries to help develop their own local lists of essential medicine . These are the medications to which people should have access at all times in sufficient amounts. The prices should be at generally affordable levels. and the concept of EDL is to lead : better health care . better drug management . lowers costs .