In this report, we propose a philosophy of treatment that few physicians may be bold enough to actually embrace, but which we believe may eventually find a place in the oncologist's armamentarium. The proposal is based on two assumptions: (1) that many hormones and other biologicals have reverse effects in biologic systems depending on their dosage or concentration, a phenomenon called hormesis; and (2) that most malignant tumors have a large but slow-moving capacity to adapt to adverse conditions, probably by the selection of cellular variants. We suggest that the phenomenon of hormesis might be used to keep a tumor under hormonal and/or immunologic environments that are inimical to its growth and well-being.