In this paper, the effect of the concentrate of liquor made from dried sweet potato on the proliferation of tetrahymena pyriformis has been studied.The toxicity of ,d,-2,3-butanediol and ethanol have also been investigated by the tetrahymena pyriformis and it has been found that they didn′t produce the effect on the propagation of the cell up to 250 and 1000 ppm, separately. The unirradiated concentrate of the different batch liquors all appear more or less the inhibition on the proliferation of tetrahymena pyriformis. The effect is more remarkable for the concentrate of the irradiated liquors and is strengthened as increase of absorbed dose. It shows that the toxicity of the concentrate of the irradiated liquor to tetrahymena pyriformis may be related to the quality of the dried sweet potato used and the formation of radiolytic products with higher boiling point.