This paper reports the antimutagenesis effect of three different preparations of five kinds of Chongqing green tea on four direct and indirect mutagens with Ames test.The results show that acetone extracts and concentrated water extracts of all the above green teas markedly inhibit the mutagenicity of AFB1 and B(a)P.The inhibition rate is above 89%

and the dose-response relation is clear. The inhibition rate of drinking concentration of water extract of the teas for mutagenicity of AFB1 and B(a) P is above 70%. But neither the acetone extracts nor the water extracts of the above green tea inhibit the mutagenicity of the two direct mutagens-2

7-diaminofluorene and sodium azide

the inhibition rates are all below 20%. The possible mechanisms of action are being discussed