Objective:To determine the effect of isopsoralen on the osteogensis and adipogenesis of bone marrow mesenchymal stem cells(BM-MSCs). Methods:Rat BM-MSCs were cultured in the absence or presence of isopsoralen for 14 days,and resulting cells were stained with methylene blue, Oil Red O and detected for alkaline phosphatase(ALP). RNA and protein were isolated from cells,and expression levels of osteogenesis and adipogenesis related genes were evaluated by RT-PCR and Western blot. Results:①The efficiency of CFU-f and ALP positive CFU-f formation by BM-MSCs was enhanced,and the expressions of osteogenesis related genes were up-regulated significantly in isopsoralen-treated cultures compared with control cultures. ②The adipocyte forming efficiency and the gene and protein expressions of peroxisome proliferator-activated receptor-γ(PPARγ) were inhibited significantly in isopsoralen-treated cultures compared with control cultures. Conclusion:Our results indicate that isopsoralen can stimulate osteogensis and inhibit adipogenesis of BM-MSCs,and the stimulating effect of isopsoralen is better than psoralen.