Abstract: An electro-cellular counter was used to determine the effect of various anticancerous drugson marrow cells. Using this method, we determined the action of 8 anticancerous drugs marrow cells is healthy adults. Our data revealed that: 1. Normal marrow cells were highly sensitive to AD and Harringtonine. 50％—80％ of the population were sensitive bodies. However AD and Harringtonine were highly toxic. 2. Sensitivities of normal marrow cells to VCR, MTX, CC. 6MP, 6TG. and Ara-c were relatively lower, 10％—30％ of the population determined were sensitive bodies. These 6 drugs seemed less toxic to the normal bone marrow cells and hence way be the drugs of choice for the clinical use.