Over the period; medical science has evolved from the supernatural theory to a modern science. The subject Preventive & Social Medicine (PSM) is the relatively newer discipline conceptualized in the early twentieth century. Even after its conception, it has kept on growing and changed. It started as only preventive medicine which was to be applied to healthy people, customarily by actions affecting large population, with primary objective to disease prevention and health promotion.

Later on a social medicine which emphasizes the strong relationships between medicine and social science, and deals with more of study of epidemiology and medical care of society came on the surface.

Another discipline, Public Health; borne out of a sanitary awakening movement following the industrial revolution and its consequences on the people’s health on the western sphere of the world in the early nineteenth century and largely dealing with sanitation and hygiene, i.e. clean water, clean surroundings, wholesome conditions of houses, control of offensive trades, etc. also shares some common objectives and areas.

All the three disciples are standing on the common foundation and are sharing many common areas, hence the term and role of these disciplines are many time used interchangeably, hence now a day the comprehensive terminology Community Medicine are also advocated by many people.

Overall expected roles of the PSM experts are…

·    To use of epidemiology as a scientific tool to make rational decision relevant to community and individual for preventive, promotive, curative and rehabilitative care.
·    To investigate an outbreak or epidemic identifying the causes/factors and suggest the measures.
·    To diagnosis and manage public health problems prevailing in the community keeping in mind the existing health care system  in the context of the prevailing socio-cultural beliefs.