Mass gathering medicine, also known as event medicine, crowd medicine or mass gathering health, is a field of medicine that explores the health effects/risks of mass gatherings and the strategies that contribute positively to effective health services delivery during these events.The reason for the development of the field of medicine gives the fact that mass gatherings generate a higher incidence of injury and illness, may be the subject to a catastrophic accident or attack with large numbers of injured or dead persons. Key purposes of Mass Gathering Medical Services at an event are: