The purpose of this study was to elucidate effects of fructooligosaccharide on gastrointestinal tract and blood lipids of rats when this was supplied as purchased condition or oligosaccharide containing sponge cake. Male Sprague-Dawley rats were assigned to one of 3 treatments 1) control diet 2) 7.5% fructooligosaccharide containing diet (FOS diet) 3) lyophilized sponge cake powder containing diet (FOS-C diet). The sponge cake was made with fractooligosaccharide which replaced 40% of its surose, and the final concentration of fructooligosaccharide in FOS-C diet was 7.5%. Cecal and fecal water contents, amount of cecal content, and cecal wall weight were higher from fructooligosaccharide consumption, whereas total gut transit time was longer in rats consuming fructooligosaccharide compared with those fed control diet. Cecal and fecal pH were lower in FOS and FOS-C groups than in control group. Total cecal SCFA pools were higher from ingesting fructooligosaccharide containing diets compared with control diet. Serum triglyceride levels were lower in rats fed FOS and FOS-C diet than those fed control diet, while serum cholesterol levels were unaffected by treatment. Therefore the effects of fructooligosaccharide in sponge cake on serum lipids and gastrointestinal tract were similar to those of intact fructooligosaccharide. Also, adding 7.5% of FOS accompanied diarrhea symptom which suggests some precaution are needed when using FOS.