Fowlie 1992.

Methods	RCT
Participants	49 patients Gastro intestinal outpatient clinic Mean age 40 years 65% female Mean duration of symptoms 3.8 years
Interventions	Bulking agent 3 months mixed cereal and fruit fibre 4.1 g/day
Outcomes	Abdominal pain Global assessment Symptom score
Notes	GI Outpatients 1 week run‐in
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Low risk	Adequate
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, identical placebo
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing outcome data balanced in numbers across intervention groups with similar reasons for missing data across groups
Selective reporting (reporting bias)	Low risk	All expected outcomes were reported
Other bias	Low risk	The study appears to be free of other sources of bias