COSAN toxicity to nuclear cells matched its hemolytic toxicity, with COSAN inhibiting 50% of cell proliferation (IC50) in the concentration range from 29.3 to 106.6 µM depending on the cell line (Table , Figure ). In other words, COSAN affects nuclear cell viability at concentrations similar to those that induce RBC membrane disruption. Although these results suggest that COSAN toxicity to nuclear cells also involves cell membrane disruption, further studies must be conducted to confirm this hypothesis. Abbreviations: EC50 -half maximal effective concentration of hemolysis, IC50 -half maximal inhibitory concentration of proliferation; the values of the 95% confidence interval (95% CI) are presented in brackets.