Liu 1997.

Methods	RCT
Participants	101 IBS patients Unclear setting 40% females
Interventions	Spasmolytic 4 weeks peppermint oil tds‐qid 187 mg
Outcomes	Abdominal pain, dichotomous
Notes	No run‐in
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	Low risk	Double‐blind, identical placebo
Incomplete outcome data (attrition bias) All outcomes	Low risk	9 drop‐outs: 3 patients on Colpermin and 6 on placebo did not return for follow‐up
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