Abstract: The present experimental physiological study on male Guinea pigs aims to examine the effects of the Chinese Danshen roots aqueous extract on the blood coagulation parameters. Animals in two treated groups (G2) and (G3) were given daily two therapeutic doses for 15 days (21 and 43 mg kg-1, respectively). The current results of the haematological measurements showed that Danshen roots extract induced marked significant inhibitory effects on the blood coagulation parameters, mainly under the influence of the high therapeutic dose (43 mg kg-1). Under this dose, significant increases were recorded in the means of Prothrombin time, INR and APTT (66.80 ±1.8 sec, 11 and 56.60 ±2.7 sec, respectively) compared to the control group. On the other hand, significant decreases were recorded in means of serum Fibrinogen level and Fibrin degraded products (1.65 ±0.12 g L-1 and 0.63 ±0.05 mg L-1, respectively) compared to the control group. Similarly, significant decreases were observed in the means of the following coagulation parameters:- Factor (IX), Factor (VIII), Anti-thrombin (III), Protein C and protein S (29, 46, 57, 61 and 24%, respectively) compared to control group. In conclusion, the results can be considered as an indicator proving the hypocoagulative effect of the active compounds of Danshen roots on blood coagulation process. Hence, this useful therapeutic effect can be used in the treatment of thrombosis cases in human patients. But, further pharmacological and toxicological studies should be performed to examine the therapeutic safety of Danshen roots.