We clarified how raffinose, one of the non-digestive oligosaccharides, reaches the large intestine. Seven healthy male volunteers were given a test meal containing 10.0 g raffinose. A double-lumen tube was placed in the terminal ileum, and the ileal contents were aspirated through the tube. The amounts of raffinose were orally administered and collected from the terminal ileum and were compared with each other. The result was that the mean+/-standard error percentage of the amount of ingested raffinose collected in the terminal ileum was 97.1+/-2.4%. Furthermore, the average times taken for 20%, 40%, 60% and 80% of raffinose to reach the terminal ileum were 2.0+/-0.6 h, 2.6+/-0.7 h, 3.6+/-0.7 h and 4.9+/-0.7 h, respectively. In conclusion, approximately 100% of ingested raffinose was recovered in the terminal ileum in the present study. This corresponds with the present generally accepted definition of a dietary fibre.