Abstract: The present invention relates to cytostatics which have a tumor-specific action as a result of linkage to specific carbohydrate moeities via preferred linking units which can be selevtively cleaved by enzymes such as metallo matrixproteases (MMPs), elastase or cathepsines, i.e. by enzymes which can especially be found in tumor tissue. The preferred linking units guarantee sufficient serum stability of the conjugate of cytostatic and carbohydrate moeity and, at the same time, the desired intracellular action within tumor cells as a result of its specific enzymatic or hydrolytic cleavability with release of the cytostatic.