The following is an excerpt from Breaking the Viscious Cycle, by Elaine Gottschall:
What are the recognized side effects of ingesting Inulin/FOS?
Assuming one is not allergic to Inulin/FOS, the typical side effects will vary depending on one's level of tolerance. The list of known side effects include: flatulence, bloating, cramps, abdominal pain, and diarrhea. As Inluin/FOS permeates our food supply, the list of side effects is expected to grow.
The whole statement regarding the ingestion of inulin can be found at: