A series of polymeric carrier drugs were prepared by linking 5-fluorouracil to chitosan as a carrier. The conversion of H2N- group in chitosan was estimated by the determination of nitrogen content
and the structure of polymeric carrier drugs was confirmed by IR
UV and 13C-NMR. Hydrolytic release of 5-fluorouracil or its derivatives from these new polymeric carrier drugs was also investigated. The preliminary results of the in vitro testing against Ehrlich Asci-tes Carcinoma cell showed that I and II type of polymeric drugs have good antitumor activity.