Each year approximately 9800 papers on trace elements are published. Of these, approximately 75 deal with trace elements and hair. Review articles appear annually. Some of these studies demonstrate that the mean concentration of an essential trace element is lower or that of a potentially toxic element is higher in the hair of a group of people afflicted with a specific disease. Associations between hair analyses and demographic variables have been found. Fewer studies have shown a correlation between essential elements in hair of animals and the same elements in organs. It is possible to measure trace elements in hair to satisfy the skeptical chemist. Although such measurement is a necessary prelude toward medical utility, it is not sufficient. Hair analysis seems potentially useful in experimental medicine but its use in clinical medicine for diagnosis, prognosis, and therapy will remain limited until validation by the standard methods of clinical investigation is achieved.