The chromosomal aberration of the trichothecene mycotoxins such as T-2 toxin (T-2), HT-2 toxin (HT-2), nivalenol (NIV) and deoxynivalenol (DON) which are one of the most important food borne contaminants produced by Fusarium species fungi, was investigated in the chinese hamster lung cells. These trichothecene mycotoxins showed high cytotoxicity in order of T-2, HT-2, NIV, and DON to the chinese hamster lung cells. Nevertheless high cytotoxicity of these trichothecene mycotoxins, no clastogenicity of T-2 and HT-2 in the range of 0.01-0.0025 ng/ml, of NIV in that of 0.3-0.075ng/ml, and of DON in that of 1.0-0.25 ng/ml was observed in both with and without metabolic activation system.