Fermentation by Lactobacillus curvatus improves the beneficial effect of hwangryun-haedok-tang (HRT), a traditional herbal medicine, on postmenopausal osteoporosis by enhancing the inhibitory effect of this medicine on osteoclastogenesis (Shim et al., 2013). It has been shown that fermentation of HRT generates the different flavonoid profile compared to non-fermented HRT. More specifically, fermentation of HRT changes the concentration of geniposide (−28%), baicalin (+249%), berberine (+2.5%), and palmatine (+4%) when compared to unfermented HRT (Shim et al., 2013). It has been suggested that in addition to generation of the bioactive components of flavonoid, bacterial fermentation is also able to change the structure of the flavonoids. For example, bacterial fermentation de-glycosylates, sulfates, or methylates flavonoids, which modulates the absorption rate and metabolism in the liver (Scalbert & Williamson, 2000). More specifically, bacterial fermentation-mediated structural changes in flavonoids accelerate the absorption rate and the amounts absorbed which might improve the bioactivity and bioavailability of the active ingredients (Hendrich, 2002; Izumi et al., 2000) and might contribute to the beneficial impact on bone (Scholz-Ahrens et al., 2007).