In this study, we determined the glycemic index (GI) of an herbal preparation (Insu $100^{(R)}$; Korean red ginseng, carob, mulberry, and banaba). Ten subjects (men and women) took part in standard glycemic testing during a 4-week study period (with duplicate trials of each treatment). Informed consent was obtained from each subject. No adverse effects resulted from the administration of the herbal preparation. The GI of Insu $100^{(R)}$ was $19.5{pm}5.1$, indicating that administration of this herbal cocktail may be beneficial to people with metabolic disorders and to those who wish to maintain their overall health. This study complied with the Declaration of Helsinki.