In order to study effects of Yukmiziwhang-Whan on the growth of rats, we divided the experimental rats into two groups(Control&Sample groups) and peformed the experimental study. Sample group was administered the extract of Yukmiziwhang-Whan 1.6ml/100g for 4 weeks, and Control group was administered equal dose of normal saline. We measured the body weight, the length of femur and tibia, the level of serum growth hormone, T3, T4, Insulin and testosterone. The results are summarized as follows : 1) The body weight was not changed compared with Control group. 2) The lengths of femur and tibia in the Sample group was longer than that of Control group, but it was not statistically significant. 3) The level of serum growth hormone in the Sample group significantly increased compared with Control group(p<0.05). 4) The level of serum T3 in the Sample group significantly increased compared with Control group(p<0.05) and T4 level was trending toward increasing compared with Control group. 5) The level of serum insulin in the Sample group was trending toward increase compared with Control group. 6) The level of serum testosterone in the Sample group was trending toward decrease compared with Control group. According to the above experimental results, ${ulcorner}Yukmiziwhang-Whan{lrcorner}$ are assumed to have effective activity on the growth of rats.