Several growth factors and polypeptidesare not commonly yet used for regenerators of bone tissue or alveolar bone because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many natural medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, anti-inflammatory and regenerative potential of periodontal tissues. Olibanum, Myrrha, Phlomis Radix, and Cimicifugae Rhizoma have been traditionally used as a drug for treatment of bone disease in oriental medicine. The objective of this study was to examine the ability of alkaline phosphatase(ALP) synthesis of rat calvarial osteoblast(MC3T3-E1) when several natural medicines were supplemented. MC3T3-E1 cells were cultured with ${alpha}$-MEM(negative control), dexamethasone(positive control), and each natural medicines for 3 and 5 days. And then ALP synthesis was measured by spectrophotometer for enzyme activity and by naphthol AS-BI staining for morphometry. All of the natural medicines induced higher activity of ALP synthesis than the negative controls. Especially Olibanumind uced the higher activity than the positive controls (p<0.05). In the aspects of culturing time, except Cimicifugae Rhizoma, the natural medicines induced higher activity of ALP synthesis at 5 days than at 3 days (p<0.05). In morphometry, all of the natural medicines showed statistical significance compared to the negative control (p<0.05). Myrrha a n d Phlomis Radix showed larger positively stained area at 5days than at 3 days, whereas the others did not showed the difference between at 5 and at 3 days(p<0.05). These results indicate that several natural medicines have an inducing ability of ALP synthesis in MC3T3-E1 cells.