Objective To evaluate preliminarily safety and effect of Luo Tai injection, and to observe some values of physiology, biochemistry and hemorrheology in rhesus monkey. Methods The animals in two groups were treated daily by 40mg/kg and 24mg/kg in intravenous infusion separately for two period of treatment. The physiological changes were observed every day. Some values of biochemistry, hemorrheology were detected and compared at the early, medium and later stages of treatment. Results There was no effects on physiological function, liver and kidney function in rhesus monkey. The fibrinogen, hematocrit values in test groups were significant lower than those in control group ( P <0 01, P <0 001), and whole blood viscosity, plasma viscosity were lower in the low dose group ( P <0 05). Conclusion Luo Tai injection has obvious function to reduce blood viscosity level in rhesus monkey, and it is safe and effective.