Three different dosage groups for the mixed plant extract of hansogdan (Phlomis umbrosa) and dalgaebi (Commelina communis) (5, 25, and 100 mg/kg/day respectively) were evaluated in rats for the investigation of the enhancement of growth of physical height as a milk additive. Comparing to control group, the nose-to-tail (N-T) length was significantly increased in all treatment groups with a dose dependent manner, nose-to-anus (N-A) length was increased significantly in 25 and 100 mg/kg groups, the increase in both N-T and N-A lengths in 100 mg/kg group was almost same to that of positive group, and the femoral bone length in 25 mg/kg group was significantly increased. In result, the consumption of the mixed extract with milk could stimulate the longitudinal growth and that the addition of the mixed herbal extract into the milk could be more effective than milk itself in terms of the growth of physical height in rats.