There are no recommendations for assessing the effect of potential drugs on the hemostatic system irrespective of the anticipated application area, which leads to long-term financial losses. The examples of papaverine hydrochloride, pentoxifylline, and acetylsalicylic acid demonstrated the potential of thromboelastography (TEG) as a screening method for products that affect the hemostatic system, the safety assessment method for hypercoagulability/hypocoagulability, and the thrombosis model, using tissue factor (TF) or thrombin. The blood of male donor patients (n = 60) with acute de novo thrombosis (n = 90) was used. Using activated TEG, in vitro hemostatic system hyperactivity modeling was carried out with the blood of healthy male donors (n = 20); 0.2 М CaCl2, recombinant TF, and thrombin were used as TEG activators. General coagulation tendency (R), functional activity of thrombocytes and fibrinogens (МА, Angle), fibrinolysis activity, and physical-mechanical properties of formed clots were determined from thromboelastograms. The effect of anti-aggregants was characterized by a significant decrease in МА. The potential of TEG as a screening method for assessing the effect of new pharmacological agents on the hemostatic system at preclinical stage was demonstrated; the possibility of safety assessment for hypercoagulability/hypocoagulability was shown; and the comparability of hemostatic parameters of the patients with thrombosis and TEG, activated by TF and/or thrombin was demonstrated.