We investigated the effect of a green seaweed Capsosiphon fulvescens extract (CFE) on the serum, liver tissue, and fecal cholesterol levels in rats. Male Sprague-Dawley rats (four weeks old) were given on of three diets for four weeks: basal, high cholesterol, and CFE, The total serum and liver tissue cholesterol levels in the CFE group were significantly decreased compared to those in the cholesterol group. The CFE group showed increased amounts of feces, total fecal bile acid and dietary fiber as compared to basal and cholesterol group. Hematoxylin and eosin staining revealed fat droplets in the livers of the rats in the cholesterol group; however, a decreased number of droplets was observed in the rats fed the CFE diet. Our results suggest that CFE supplementation may improve lipid metabolism, by controling serum and liver tissue cholesterol levels, and by increasing the total amounts of bile acid, dietary fiber and cholesterol excretion in feces.