Rees 2005.

Methods	RCT
Participants	28 patients GI out clinic Rome criteria Mean age 36.1 years 86% female
Interventions	Bulking agent 10‐20 g coarse wheat bran once daily for 8 to 12 weeks
Outcomes	Abdominal pain, continuous Global assessment, dichotomous
Notes	No run in period
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Single‐blind (patients)
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 patients dropped out from treatment group and 4 dropped out from placebo
Selective reporting (reporting bias)	Low risk	Expected outcomes were reported
Other bias	Low risk	The study appears to be free of other sources of bias