The cytotoxic effects on human lymphocytes of Hemolysin sample (one pure sample produced in the laboratory for this study) were assessed at four different concentrations (25, 50, 100 and 200 μL) using the methylthiazol tetrazolium (MTT) bioassay. The results showed that growth was inhibited by 21.4, 32.3, 48.7, and 79.34 for each of the four concentrations of the pure sample, respectively, Deoxyribonucleic acid (DNA) was extracted from the lymphocytes and analysed by electrophoresis on a 1% agarose gel. Hemolysin appeared to have the ability to degrade or damage the DNA. The present study showed that both the growth inhibition and DNA damage experienced by the human lymphocytes increased linearly with increasing concentrations of the toxin.