Dicentric chromosome analysis (DCA) is the gold standard for individual radiation dose estimation. Two limiting factors of DCA are the time-consuming lymphocyte stimulation and proliferation using the lectin PHA-M and the upper dose limit of individual dose assessment of ∼4 Gy. By measuring the mitotic index (MI), the authors investigated systematically whether the stimulation of lymphocytes can be improved after administration of alternative (and combined) mitogens. The authors compared the lymphocyte stimulation effectiveness of the traditionally used PHA-M (from Phaseolus vulgaris) with seven cited mitogens by determination of MIs: five lectins namely CNA (concanavalin A), PW (pokeweed), LMA (Maackia amurensis), LTV (T. vulgaris), PHA-L (P. vulgaris) as well as LPS (lipopolysaccharide, Escherichia coli) and SLO (streptolysine O, Streptococcus pyogenes) were applied. The conventional protocol using PHA-M for lymphocyte stimulation proved to be superior over lower/higher PHA-M concentrations as well as seven other mitogens administered either alone or combined with SLO or LPS.