Abstract: The in vitro cytotoxicities of different degrees of substitution and different concentrations of carboxymethyl konjac glucomannan (CMKGM) were tested by MTT assay. In this study, L929 mouse fibroblasts were used as the target cells. The OD values of cultured cells were measured on the first day. The cell relative growth rates of each group were calculated. The cytotoxicitie grades of each group were determined according to six-grade. Results showed that the cytotoxicity gradation of each group is at the first grade. The tested groups have no significant difference to the negative group (p>0.05), while have significant difference to the positive group (p<0.01). The concentration of carboxymethyl konjac glucomannan has significant influence on cell activity.

Key words: MTT-assay, carboxymethyl konjac glucomannan, cytotoxicity