Abstract: In order to assess the roles of the carbohydrate side chain and aglycon part of steroid glycosides in influencing antineoplastic activities of these compounds,the antiproliferative activities against human cervical carcinoma( Hela),liver cancer( H7402) and mouse fibroblast( L929) cells of a series of structurally related individual compounds including dioscin,gracillin,solamargine,solasonine and chaconine,were examined using a microculture tetrazolium( MTT) assay. And then,the antiproliferative activities against human colonic cancer( HCT-8) cells of a series of chemically modified steroid glycosides including 6-O-sulfated chaconine,6,6'-di-O-sulfated solanine and per-O-acetyled chaconine were examined using a MTT assay.The results showed that the antiproliferative activity of the chacotriose-containing steroid glycosides dioscin,chaconine and solamargine was higher significantly than other trisaccharide-containing steroid glycosides solasonine and gracillin. The effectiveness against the human carcinoma cells was greater than against the mouse fibroblast cells.6-O-sulfated chaconine,6,6'-di-O-sulfated solanine and per-O-acetyled chaconine shown no antiproliferative activity against human HCT-8 cells. Structure-activity relationship studies indicated that the F ring structure of the aglycon unit influence biological activity; the composition,nature and the order of attachment of the sugars in the oligosaccharide associated with the steroid glycosides,were important in the antineoplastic properties; the-OH group of the sugar molecules seem to be an vital factor related to antineoplastic activity.