This study examined the growth effects of yeast hydrolysate (YH) and a traditional Korean herbal mixture (HM, a mixture of safflower seed and gasiogapi extract). Three-week old male SD rats were divided into the following five groups: negative control (saline), positive control (foremilk 0.5 g/kg/day), YH (YH 0.5 g/kg/day), HM (HM 0.2 g/kg/day), and YH+HM (YH 0.5 g/kg/day and HM 0.2 g/kg/day). Tibia bone length was 9.22 mm in the normal control rats, while both the YH and YH+HM groups had significantly longer tibia bones than the control rats (9.75 mm and 10.46 mm, respectively). The proximal epiphyses of YH, HM, and YH+HM measured 0.75, 0.70, and 0.75 mm, respectively, while the length in the control group was 0.50 mm. Plasma insulin growth factor-1 (IGF-1) level was slightly higher in the YH group (1.36 mg/mL) than in the control rats (1.29 mg/mL), but the difference was not significant. Plasma IGF-1 level was significantly increased in the HM (1.49 mg/mL) and YH+HM (1.53 mg/mL) groups compared to the control group (1.29 mg/mL). Growth hormone (GH) levels in YH (17.45 ng/mL), HM (15.49 ng/mL), and YH+HM (16.07 ng/mL) were significantly different compared to the control group (3.63 ng/mL).