Capanni 2005.

Methods	RCT
Participants	178 patients secondary care Rome II criteria Mean age 42 years 75% female
Interventions	Spasmolytics peppermint oil for 3 months, dose not stated
Outcomes	Global assessment, dichotomous IBS‐symptoms, dichotomous
Notes	4 weeks run‐in Dosage of intervention not clear
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Described as double‐blind
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 drop‐outs from peppermint oil group and 2 drop‐outs from placebo
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