This study was performed to investigate therapeutic effects of Achyranthis Radix extract and chitosan on the growth and differentiation of rat calvarial cells. it was found that treatment of methanol extract of Achyranthis Radix for 2 days caused 2.4-fold increase in the growth of rat calvarial cells. However, chitosan treatment caused only 1.9-fold increase in the cell growth. Treatment of methanol extract of Achyranthis Radix for 14 days caused 2-fold increase in the growth of rat calvarial cells. Alkaline phosphatase activity, one of the markers for bone cell differentiation, was increased approximately by 1.7-fold and 2.9-fold by the treatment of methanol extract of Achyranthis Radix for 2 days and 14 days, respectively. These results suggest that Achyranthis Radix extract could be beneficial for bone regeneration.