Oral Cancer is a neoplasm with a fairly large male to female ration in most populations. Moreover, it develops in older age in females in comparison with males, and the ration of non-smokers, non-drinkers among elderly female oral cancer cases if suprisingly high. The conspicuously lower incidence of this tumour among women than men is suggestive of certain endocrine involvement in its development. There are no available literary data as yet which would give an explanation to this gender specific incidence of oral cancer. Oral cancer is a multicasual disease and there are thorough interrelationships among the etiologic factors. Till now, exogenous harmful noxae (tobacco, alcohol comsumption and energy rich diet) were overemphasised in its epidemology. However, these exogenous factors have not only local carcinogenic effect in the oral cavity, but also induce systemtic changes by means of metabolic and hormonal pathways. With full knowledge of these correlations, isolated investigations of exogenous risk factors may be misleading. This book containing the author's results on oral cancer raises a new concept concerning tumour initiation. Not oestrogen, but its deficiency may provoke malignant transformation. This new theory may explain many controversial literary data concerning the associations of female sexual steroids and malignancies.