Cymiazole hydrochloride is the active ingredient of a synthetic systemically acting acaricide used in beekeeping (Apitol®, Apichem®). Considering that residues of cymiazole hydrochloride were detected in all bee products being used for human nutrition and as alternative medications in human and veterinary medicine, the objective of this study was to evaluate the effects of cymiazole hydrochloride on mitotic activity of cultured human lymphocytes. The mitotic and proliferation indices in phytohaemagglutinin-activated human peripheral blood lymphocytes were determined using three experimental concentrations of cymiazole hydrochloride (0.01; 0.1; 1mg/ml). All experimental concentrations of cymiazole hydrochloride increased mitotic index values (MI) by a statistically highly significant amount (p<0.001). Moreover, proliferation index (PI) was also changed very significantly (p<0.001) after each experimental cymiazole hydrochloride treatment. The dose dependent increase in proliferation index values clearly demonstrates the ability of cymiazole hydrochloride to induce significant alterations of cell cycle kinetics having an influence on G0 state and arousing cell division. This indicates a risk from consuming bee products with cymiazole hydrochloride residues particularly in those predisposed to malignant diseases. Strict respect to the withrawal time while using cymiazole hydrochloride (Apitol®, Apichem®) is of great importance because residue levels higher than the permitted one can easily occur in honey and other bee products from treated honey bee colonies.