Twentyfive plant crude drugs with traditional reputation were selected for the antithrombotic screening. MeOH (80%) extract of each plant was given (500 mg/Kg, p.o.) to mice 1 hr prior to the thrombotic challenge (1.8 mg collagen plus 180 ug epinephrine/Kg, i.v.). Seven extracts (1, 2, 8, 10, 18, 22 and 23) showed either comparable or better recovery than aspirin (50 mg/Kg, p.o.) from paralysis caused by the pulmonary thrombosis. 1, 2, 8, 10, 18, 22 and 23 were fractionated to $CH_2Cl_2$ soluble (fr I) and $H_2O$ soluble (fr II) fractions and each fraction (100 mg/Kg, p.o.) was also tested. Mice treated with fr I of 2 (Angelica koreana), 10 (Corydalis spp.) or 23 (Schizonepeta tenuifolia) showed higher recovery and lower mortality rates than aspirin (50 mg/Kg, p.o.) treated mice.