Proprietary preparations of Bitter yam (Dioscorea polygonoides) are implicated in lowering cholesterol in rats (McAnuff, 2005). Recent studies have shown that hypercholesterolemia is a growing problem worldwide. Efforts to control or minimize the incidence of cardiovascular diseases often seek to maintain the normal range for cholesterol in the blood. The main objective of this study is to assess the effect of the consumption of bitter yam proprietary preparation on kidneys of genetically modified hypercholesterolemic mice. Genetically modified male mice were fed the following diets: normal rat chow, normal rat chow supplemented with the bitter yam proprietary preparation, a high cholesterol rat chow and a high cholesterol rat chow supplemented with the bitter yam proprietary preparation. At the end of feeding period, the mice were killed and the kidneys collected. Lipid peroxidation analysis was carried out using the method of Okhawa et al 1978. Blood urea nitrogen, creatinine and electrolytes levels were determined at Indexx Laboratories Inc., USA. A significant increase (p<0.05) in lipid peroxidation was observed in the kidneys of normal and hypercholesterolemic mice fed diets supplemented with bitter yam proprietary preparation (397.33 ± 54.21 to 1522.77 ± 89.07 and 2032.26 ± 12.39 nmol MDA/g wet weight, respectively). Blood Urea Nitrogen level also increased in hypercholesterolemic mice fed a diet supplemented with bitter yam (25.00 ± 1.00 to 32.50 ± 0.50 g/dL). Significant increases were observed in the levels of serum sodium in hypercholesterolemic mice fed a high cholesterol diet and hyercholesterolemic mice fed diet supplemented with bitter yam proprietary preparation (149.5 ± 0.5 U/L to 154.0 ± 1.0 U/L and 152.5 ± 0.5 U/L, respectively). There was also a significant increase in the level of serum magnesium of the normal mice fed diet supplemented with bitter yam proprietary preparation (2.20 ± 0.00 U/L to 4.65 ± 0.35 U/L). It would appear that supplementation of the diet with 5% bitter yam proprietary preparation may cause damage to the kidneys. Lower doses of this preparation should be analysed for efficacy and safety.