Gilvarry 1989.

Methods	RCT
Participants	24 IBS patients Unclear setting Diagnostic criteria not defined Mean age 32 years 79% female
Interventions	Antispasmodic pirenzepine 100 mg for 4 weeks
Outcomes	Abdominal pain, dichotomous Global assessment, dichotomous
Notes	4 to 8 weeks run‐in with high fibre diet (> 30 g/day) continued high fibre diet during study 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	Unclear risk	Double blind, methods not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 drop outs
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