Objective:To evaluate the cytotoxicity of Adper Prompt self-etch system of bongding agents on human gingival fibroblasts by flow cytometry. Methods:Human gingival fibroblasts (HGFs) of passage 5 were cultured when cells covered 85% of the flask bottom. Different concentration (1.00 -滋l/L,0.50 -滋l/L,0.25 -滋l/L) of Adper Prompt were added- into medium respectively,and no Adper Prompt in medium as the negative control group. Cells were collected after 4 d and 7 d with 0.25% trypsin,fixed with 75% ethanol. The percentages of DNA content and apoptosis in different cycle phase were measured using flow cytometry,and the cell proliferation indexes(CPI) of different groups were calculated. Results:The peak of apoptosis rate was obvious in 1.00 -滋l/L group,and the peak of aneuploidy cell proliferation appeared in the cells treated with 1.00 -滋l/L Adper Prompt for 4 d. As compared with the control group,the DNA percentage of G2/M phase in 0.50 -滋l/L and 0.25 -滋l/L group increased significantly(P < 0.05) for both 4 d and 7 d,and while for 4 d,the DNA percentage of S phase in 1.00 -滋l/L group increased significantly (P < 0.05). The CPI of 7d is lower than that of 4d in the same concentration group. Conclusion:The cytotoxicity of Adper Prompt on human gingival fibroblasts in vitro is obvious,and it must be used very carefully in the clinic and kept away from gingives.