The present invention relates to hydroxyalkyl starch or a pharmaceutical preparation thereof for the treatment of cancer, tumor or tumor associated diseases, especially by effectively reducing tumor growth rate and inhibiting tumor growth and wherein the hydroxyalkyl starch has a mean molecular weight (MW) above 20 and below 1300 kDa and a molar substitution (MS) in the range of from 0.1 to 1.5, wherein the alkylation may be an ethylation, propylation or butylation or mixes thereof； and wherein the alkyl may be further substituted.
