This study was performed to investigate therapeutic effects of Carthami Semen, Paeoniae Raidx extracts and chitosan on the growth and differentiation of human periodontal ligament cell. We found that co-treatment of methanol extracts of Carthami Semen and chitosan significantly increased the growth of human periodontal ligament cell. However, the sigle treatment groups of the extracts showed only 20-30% of the growth increase. Alkaline phosphase activity, one of differentiation markers, was increased approximately 1.5- fold by co-treatment of methanol extract of Carthami Semen and chitosan and calcified nodule formation was also increased at the similar levels as the alkaline phosphatase. But the single treatment groups showed only 20-30% increases. These results suggest that Carthami Semen and chitosan co-treatment can be used efficiently for periodontium regeneration.