As a step toward detecting the role of resistant starch (RS), the effects of boiled rice or bread intake on evacuation were examined. Ten subjects aged 21-22 were fed two types of prescribed diets of 3 meals per day for 7 successive days. Each type consisted of a different staple food; boiled rice or bread. The subjects were fed the same type of meal for 7 days and the frequency and amount of evacuation was recorded by the subjects. Analyzing the data showed the following results. The estimated total fiber contained in the bread each subject consumed was 6.3 g/day, and the estimated total fiber contained in boiled rice was 1.4 g/day. That is, there was 4.5 times more total fiber in bread than in rice. The frequency and amount of the evacuation tended to increase when boiled rice was ingested compared with the period when bread was ingested. Based on these results, we suggest that the fibers in the boiled rice lead to an increase in the frequency and amount of stools as compared with the fiber found in bread. We speculate that more RS is contained in the boiled rice than in the bread.