DMP 504 is a high molecular weight polymer currently under development by The DuPont Merck Pharmaceutical Company as a novel bile acid sequestrant to lower serum cholesterol. To assess its safety, DMP 504 is incorporated into rodent diet for oral administration to rats and mice. An analytical method was developed to determine the accuracy and homogeneity of the blends. Since a physical separation or extraction of DMP 504 from the diet was not feasible, near-infrared spectroscopy (near-IR) was employed. The near-IR method provides accurate and precise results for blends containing 1.5-8.0% of DMP 504. Comparison of results at the 1.5% level with a cholate binding referee method is also presented. Both methods provided equivalent results for the 1.5% level.