The protective effects of BNs-3 and BNs-7, extracts of citrous orange peel, on the obesity induced by ad libitum feeding a cholesterol-containing diet to rats were investigated. The animals were fed on the diet including cholesterol (0.5%) with or without the citrous orange peel extracts BNs-3 (5%) and/or BNs-7 (0.1%) for 8 weeks. The ad libitum feeding a diet containing cholesterol to rats from 6 weeks of age increased the body weight gain compared with that of rats fed on a normal diet. Such an increase in body weights was markedly attenuated by the addition of BNs-3 or BNs-7 to the diet. Especially, a combinational feeding on BNs-3 and BNs-7 significantly reduced the body weight gain below that of normal diet-fed animals. Interestingly, the weights of abdominal adipose tis-sues surrounding epididymides were greatly reduced by the citrous orange peel extracts, in parallel with the decrease in body weights. In addition, blood concentrations of lipids including cholesterol were also lowered by the combinational treatment with BNs-3 and BNs-7. Taken together, it is suggested that the obesity and overweight produced by unrestricted overfeeding on diet with cholesterol may be partially due to the accumulation of abdominal adipose tissues, around the epididymides in rats, and that citrous orange peel extracts might exert antiobese activities by reducing the adipose tis-sues as well as blood lipid concentrations.