To improve the solubility in organic solvent of chitosan, o-benzoylchitosan was synthesized by acylation with benzoyl chloride and then used in the reaction with 2-chloro-1,3,2-dioxaphosphospholane (COP) to prepare phosphorylcholine-terminated o-benzoylchitosan (PC-BCS). PC-BCS had a structure with a phospholipid polar group characterized by FTIR and H-1 NMR. PC-BCS had been poly-substituted by a PC group, which made PC-BCS viscous liquid. The anticoagulant properties of PC-BCS were evaluated by means of blood-clotting and platelet adhesion assay. The blood-clotting assay indicated that PC-BCS could prolong the blood-clotting process. Platelet adhesion assay showed that PC-BCS could effectively inhibit the platelet adhesion and activation. (C) 2003 Wiley Periodicals, Inc.