We examined the dose-dependent effects of mucopolysaccharide polysulfate (MPS) on coagulation variables and whole-blood viscosity in human blood. Both 0.01% and 0.1% MPS significantly reduced levels of both fibrin monomer and thrombin-antithrombin III complex in a manner similar to that of 2.0 IU/ml heparin sodium. Furthermore, MPS dose-dependently decreased whole-blood viscosity, as measured with an oscillation viscometer. Because MPS can be applied in creams and gels, percutaneous application of MPS may effectively reduce whole-blood viscosity in local veins.