['Radix Dipsaci is a kidney tonifying herbal medicine with a long history of safe use for treatment of bone fractures and joint diseases in China. Previous studies have shown that Radix Dipsaci extract (RDE) could prevent bone loss in ovariectomized rats.', 'This study investigates the effect of RDE against bone loss induced by simulated microgravity.', 'A hindlimb unloading rat model was established to determine the effect of RDE on bone mineral density and bone microarchitecture. Twenty-four male Sprague-Dawley rats were divided into four groups (n\u2009=\u20096 per group): control (CON), hindlimb unloading with vehicle (HLU), hindlimb unloading treated with alendronate (HLU-ALN, 2.0\u2009mg/kg/d), and hindlimb unloading treated with RDE (HLU-RDE, 500\u2009mg/kg/d). RDE or ALN was administrated orally for 4 weeks.', 'Treatment with RDE had a positive effect on mechanical strength, BMD, BMC, bone turnover markers, and the changes in urinary calcium and phosphorus excretion. MicroCT analysis showed that RDE significantly prevented the reduction of the bone volume fraction, connectivity density, trabecular number, thickness, tissue mineral density, and tissue mineral content as well as improved the trabecular separation and structure model index.'] Does treatment of Radix Dipsaci extract prevent long bone loss induced by modeled microgravity in hindlimb unloading rats?