Aim To explore the concentration range of organic solvent which can both effectively increase solubility of the difficult soluble medicine monomer, and have low toxicity to cells, and to clarify the influence of different concentration of ethanol on curcumol efficacy.Methods Different DMSO and ethanol concentrations were diluted in culture medium and incubated with cells A549, NCI-H460, NCI-H1299, NCI-1650, LTEP-a2 and SPC-A1 for 12 h, 24 h, or 48 h, cell viability was tested by a colorimetric assay with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide(MTT), and different concentrations of ethanol with/without different concentrations of curcumol were also prepared with culture medium, then incubate with A549 and NCI-H460 cells for 24 h, and cell viability was tested by MTT as well.Results Within 48 h the solution with 0.008(V/V) DMSO or less had no significant effect on the cell A549 compared with control group, for NCI-H1650 the concentration was 0.004(V/V) or less, for NCI-H460 the result turned to be 0.002(V/V) or less, and the solution with DMSO below 0.001(V/V) had significant effect on the three other cells, NCI-H1299, LTEP-a2 and SPC-A1.While within 48 h, the liquor with 0.004(V/V) ethanol or less did not exhibit significant cytotoxic effect on the cell A549, for NCI-H460 and NCI-H1650 the result of ethanol concentration became 0.002(V/V) or less, for NCI-H1299 the data was 0.001(V/V) or less, and the liquor with ethanol below 0.001(V/V) showed significant cytotoxic effect on LTEP-a2and SPC-A1.When the proportion of ethanol in solution was below 0.01, it has no cytotoxic on cell A549 and NCI-H460, and the curcumol solution prepared with this kind of ethanol solution only represented the efficacy of curcumol on the cells.Since the solution with 0.01(V/V) ethanol dissolved the curcumol better, the cell viability changed from about 100% to about 35%.Conclusions Different organic solvent expressed different toxicity to the same cell, and the sensitivity of different cells to one organic solvent is dissimilar.and DMSO could be the optimum solvent for A549 and NCI-H1650, while the optimum solvent of NCI-H1299 is ethanol, for NCI-H460 it could be both and DMSO and ethanol, and DMSO and ethanol is not suitable for LETP-a2, SPC-A1 to be solvent.