Abstract: Objective To study the effects of Aralia edinocaulis Hand.Mazz flavonoids on bone metablism in SD rat tibia fracture model.Methods Six weeks old SD rats(25 male and 25 female) were randomly divided into five groups (10 in each group).The control group and model group were given physiological saline and the flavonoids treatment groups were given Aralia echinocauIis Hand.Mazz flavonoids at the dosages of 30,20,and 10 mg/kg·bw for 28 days.On the 4th,7th,14th,21st,and 28th day,bone metablism parameters(alkaline phosphatase,hydroxyproline,osteocalcin,and total bone collagen) of all groups were measured and compared.Results Compared with the control group,the alkaline phosphatase (ALP) (292.3±23.2 U/L),hydroxyproline(8.69±1.81 μg/mL),osteocalcin(3.88±1.15 U/L) in the model group w ere significantly decreased(P< 0.01).How ever,those indicators of the Aralia echinocauIis Hand.Mazz flavonoids groups increased significantly with the ALP of 245.7±20.9 U/L,hydroxyproline of 14.01±3.01 μg/mL,and osteocalcin of 3.12±1.10 U/L,compared with those of the model group(P< 0.01 for all).Conclusion Aralia echinocauIis Hand.Mazz flavonoids can imporve the bone metabolism in rats with tibia fracture and promote the process of fracture healing.