The effect of dietary supplementation of the two oriental medicinal prescriptions, Sypjeondaebotang or Jahyulyanggeuntang, on iron bioavailability was evaluated in rats which were depleted of iron by being fed an irondeficient diet for 4 weeks. Seventy two iron-depleted rats were randomly divided into 3 groups (n = 24) , and fld one of the following experimental diets for 4 (n = 8), 12 (n = 8), and 25 days (n = 8) : Control diet (CD), Sypjeondaebotang-supplemented diet (SD), Jahyulyanggeuntang -supplemented diet (JD). The CD contained 20 mg Fe/kg diet as FeSO4, and the SD or JD was identical except that the respective oriental medicinal prescription extract was included at the level of 4 g/kg diet. Animals fed the SD and JD for 25 days consumed significantly less food (p＜0.001), but showed no change in food efficiency ratio compared to those that were fed the CD. Serum iron concentration and transferrin saturation values were significantly higher in rats fed the SD for 25 days compared to those that were fed the CD for the same period (p < 0.05). The values of serum UIBC (p < 0.05) and TIBC (p > 0.05) were lower in rats fed the SD compared to those fed the CD. Dietary supplementation of Sypjeondaebotang during the period of iron repletion significantly increased blood levels of hemoglobin (p < 0.05) and hematocrit (p < 0.01) measured at day 12, and increased mean corpuscular volume (p < 0.05) measured at day 25, compared to the values for the CD rats. Regression analyses of hemoglobin-repletion bioassay data from rats fed the SD and JD showed the relative biological values of 123% and 99%, respectively, calculated against the slope for the CD rats. Apparent iron absorption and retention values were also significantly lower (p < 0.05) in rats fed the SD for 25 days than those for the CD rats. Based on the results from diverse biochemical indices of iron status and the chemical balance study, the effect of Jahyulyanggeuntang on iron bioavailability appears to be less prominent than that for Sypjeondaebotang. Taken together, these results indicate that Sypjeondaebotang has a positive effect in restoring iron depletion by increasing the iron bioavailability in rats.