Ethno-medicines have been playing a vital role throughout human history in the day to day healthcare routine. Before the evolution of western medicine, for thousands of years, people have been using traditional medicine for the treatment of different diseases. With cancer being the major threat to human community, ethnomedicine can have a significant role in cancer prevention and cure. Among all the medicinal plants, Ocimum sanctum Linn has certain chemo-preventive molecules and compounds that contain anti-carcinogenic properties. Ocimum tenuiflorum Linn or Holy Basil has been prominently used as a medicinal herb, since ancient times in India. Ayurveda, one of the widely practised forms of ethnomedicine in India, uses O. sanctum L. extensively in its formulations of cancer-treating medicines. It is used either with other ingredients as a concoction or as a dry extract itself. This paper deals with the anti-carcinogenic properties of the Holy Basil as studied by pharmacologists and biotechnologists that has the potential to cure different types of cancer diseases. Ocimum Sanctum has been used in different studies for its potential usage on diseases like lung cancer, skin cancer and breast cancer.