Walker 1997.

Methods	Study design: cross‐over RCT Power calculation: no Intention‐to‐treat analysis: no
Participants	Inclusion criteria Setting: single centre Country: USA Non pregnant, sexually active women between the ages of 18 and 45 years with a recurrent UTI (4 UTIs during the past year or at least one during the previous 3 months); sexually active women Number: 19 randomised; 10 analysed Age range (median): 28‐44 years (37) Exclusion criteria: NS
Interventions	Treatment group Cranberry capsules: 400 mg of cranberry solids (number/d NS) Control group Placebo capsule Duration of treatment: each patient had 3 months of active treatment and 3 months placebo
Outcomes	Symptomatic UTI
Notes	Method of obtaining urine sample: NS Dedfinition of symptomatic UTI Women notified the physician and then submitted a urine sample (method: NS) To ensure a consistent entry point into the study, each participant was held in a queue until suffering a symptomatic UTI Each subsequent UTI episode was treated with antibiotics
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	NS
Allocation concealment (selection bias)	Low risk	States clinicians unaware of allocation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	States double blinding and opaque matching bottles
Blinding of outcome assessment (detection bias) All outcomes	Low risk	States double blind, likely that culture results read without knowledge of treatment arm
Incomplete outcome data (attrition bias) All outcomes	High risk	Unclear reporting of results, culture appears the units rather than patients Losses to follow‐up/withdrawals: 9
Selective reporting (reporting bias)	Low risk	Symptomatic UTI most appropriate outcome
Other bias	Unclear risk	Not well reported, difficult to assess Source of funding: NS (capsules provided by Solaray, Inc)