Compositions, pharmaceutical preparations and methods are disclosed for protecting non-neoplastic cells from damage caused by cancer chemotherapeutic agents or radiation therapy, during the course of cancer therapy or bone marrow transplant. These are based on the use of chemoprotective inducing agents that induce or increase production of cellular detoxification enzymes in target cell populations. The compositions and methods are useful to reduce or prevent hair loss, gastrointestinal distress and lesions of the skin and oral mucosa that commonly occur in patients undergoing cancer therapy. Also disclosed is a novel assay system for identifying new chemoprotective inducing agents.