The clinical effects of dosage during the period of treatment of Lithospermum Ruderale extract-a kind of Chinese traditional herbal medicine-on medicinal abortion induced by mifepristone and misoprostol were studied. Lithospermum Ruderale extract was administrated 3 d before, 3 d after or 3 d before plus 3 d after the administration of misoprostol respectively. The dose of Lithospermum Ruderale extract was 50 g, 75 g or 100 g respectively. Thus 1 350 women of early pregnancy were grouped into 9 groups and observed. The results showed that the effects of Lithospermum Ruderale used 3 d before, and 3 d before plus 3 d after (6 days misoprostol were significantly better than those only used 3 d after misoprostol both for complete abortion and bleeding (P<0.05). The dosage between 50 g and 100 g made no significant difference in clinical effects. Therefore it is reasonable to use 50 g Lithospermum Ruderale before misoprostol to improve medicinal abortion. The clinical effects of dosage during the period of treatment of Lithospermum Ruderale extract-a kind of Chinese traditional herbal medicine-on medicinal abortion induced by mifepristone and misoprostol were studied. Lithospermum Ruderale extract was administered 3 d before, 3 d after or 3 d before plus 3 d after the administration of misoprostol respectively. The dose of Lithospermum Ruderale extract was 50 g, 75 g or 100 g respectively. Thus 1 350 women of early pregnancy were grouped into 9 groups and observed. The results showed that the effects of Lithospermum Ruderale used 3 d before, and 3 d before plus 3 d after (6 days misoprostol were significantly better than those only used 3 d after misoprostol both for complete abortion and bleeding (P <0.05). The dosage between 50 g and 100 g made no significant difference in clinical effects. It it reasonable to use 50 g Lithospermum Ruderale before misoprostol to improve medicinal abortion.