It is quite complex to evaluate the mechanism of action for antitumor drugs on cancer cells.Studies have pointed out that there is an unique advantage of Fourier transform infrared spectrum to obtain a fingerprint of all molecules present in the cells when cancer cells were exposed to anti-cancer drugs.Trichostatin A(TSA) is a most potent reversible inhibitor of mammalian histone deacetylases.It can inhibit cancer cell growth in vitro and in vivo.In the present study,HeLa cells were exposed to 0,50,100,200,300 and 400 nmol·L-1 TSA,and FTIR spectra were applied to evaluate the effect of TSA on cancer cells.Results show that there is some significant relationship between the changes in FTIR absorption and cell cycle arresting.On the other hand,this investigation shows that the concentration of TSA had to be more than 200 nmol·L-1 in order to ensure A1 080 cm-1/A1 540 cm-1≥1 for inhibiting cell proliferation. It is quite complex to evaluate the mechanism of action for antitumor drugs on cancer cells. Studes have pointed out that there is an unique advantage of Fourier transform infrared spectrum to obtain a fingerprint of all molecules present in the cells when cancer cells were exposed to anti -cancer drugs.Trichostatin A (TSA) is a most potent reversible inhibitor of mammalian histone deacetylases. It can inhibit cancer cell growth in vitro and in vivo. In the present study, HeLa cells were exposed to 0, 50, 100, 200, 300 and 400 nmol·L -1 TSA, and FTIR spectra were applied to evaluate the effect of TSA on cancer cells. Results show that there is some significant relationship between the changes in FTIR absorption and cell cycle arresting. On the other hand, this investigation shows that the concentration of TSA had to be more than 200 nmol·L-1 in order to ensure A1 080 cm-1 / A1 540 cm-1 ≧ 1 for inhibiting cell proliferation.