Medical nanotechnology is a popular concept among nanotechnologists which, they say ,would totally change the world of medicine once its realised Nanomedicine would make use of tiny nanobots,which could be introduced into the body to repair or detect damages and infections.A typical blood borne medical nanobot would be around 3 microns in size ,because that is the maximum size possible due to capillary passage requiement.carbon would be the element used to build these nanobots due to the inherent strength and other characteristics of some forms of carbon (diamond/fullerene composites). Cancer can be treated very effectively, according to nanomed advocates.Today ,We have the problem of identifying and isolating cancer cells.To counter this nanobots could be in introduced into the blood stream .These bots would search out cancer affected cells using certain molecular markers .Medical bots would then destroy these cells ,and only these cells.This could be very helpful,since current treatments like radiaton and chemotherapy often end up destroying more healthy cells than cancerous ones.Robert Freitas[1]is a leading researcher of nanomedicine .He has published a book on the possibilities of nanomedicine .