Rumex crispus (Curled Dock, Polygonaceae) is a perennial wild plant used in traditional medicine as a laxative, astringent, and to treat blood and skin disease. The ethanol extract of R. crispus was obtained and its carbohydrate contents were analyzed using high-performance anion-exchange chromatography with pulsed amperometric detection. The anabolic effects of R. crispus in human osteoblastic MG-63 cells were investigated using the WST-8 assay, alkalinephosphatase (ALP) assay, and mineralization assay. The ethanol extract increased the proliferation of MG-63 cells and stimulated ALP activity in a dose-dependent manner over a 72-hrs period. Additionally, the ethanol extract dose-dependently stimulated the formation of bone nodules in MG-63 cells treated for 12 days. The ethyl acetate fraction from the ethanol extract did not affect osteoblast viability but induced an increase in ALP activity. In conclusion, the ethanol extract of R. crispus increases the proliferation and bone-forming activity of osteoblasts, and hence it could be used in the development of bone-forming stimulatory nutraceuticals and osteoporosis-related medicines.