Abstract: Chemotherapy and radiotherapy are still the main weapons in the scientist`s war against malignant disease. However, the results are far from the ideal treatment, which can be defined as `the treatment that can selectively kill the malignant cell sparing the normal healthy tissue and the function of the vital organs`. Tissue culture of human lung cancer cells and mice leukemia cells were compared with that of normal (human skin fibroblasts) in studying the effect of PM 701. This agent proved to induce apoptosis of the cancer cells without detrimental effect on normal cells; through its effect on the nuclei, limiting the division of cells, causing degeneration in apoptotic manner. PM 701 exhibited nourishing effects on normal skin fibroblasts. This implies that this agent may have selectively caner-cell killing- and reparative-effect on normal dividing cells. The present study represents the first experience in using PM 701 as a selective anti-cancer agent at tissue culture level. PM 701 is a natural product, readily available, cheap, sterile and non-toxic according to chemical and microbiological testing and proved effectiveness of this agent is reproducible on both cell lines used in the experiments.