Nuclear Division Index (NDI) is calculated to assess the effects of decoction on the proliferative capacity of human lymphocytes . From NDI values calculated in the present investigation, it was apparent that bleomycin caused a delay in cell proliferation, manifested by a change in relative numbers of cells with one nucleus to cells with four nuclei (M1 to M4 cells). The NDI values in lymphocytes exposed to bleomycin alone are similar to those reported by other investigators . In general, different types of ionizing radiation delay lymphocyte cell cycle and the extent of such delay depends on the dose delivered. An average mitotic delay of about 1 h per 1 Gy of gamma radiation has been observed once lymphocytes are exposed to ionizing radiation . These delays in cell cycle allow the cell to repair DNA and try to reduce the adverse effects of the irradiation . Normalization of NDI in bleomycin exposed lymphocytes that are previously treated with the decoction supports the protection mediated by the decoction against radiation induced damage.