Thomson 1990.

Methods	Study design: double blind randomised clinical trial. Method of randomisation: randomly allocated.
Participants	Country: United Kingdom. Setting: not stated. Number randomised: 49, treatment group 25, control group 24. Age: not stated. Sex: not stated. Inclusion criteria: Patients with PAD (stage IIb according to Fontaine) affecting the iliac or femoral arteries, involving predominantly one leg. Exclusion criteria: ICD > 300 metres; alternating side of pain; poorly controlled diabetes; significant concomitant illness.
Interventions	Treatment: Ginkgo biloba extract (Tanakan®). Control: placebo. Duration: 24 weeks.
Outcomes	Walking distance: ICD by treadmill testing (4 km/h and 10 degrees (= 17.6% incline)); recovery times; systolic ankle pressure at rest and after exercise; tolerance.
Notes	Funding: The work was supported and assisted by Ipsen International (one of the manufacturers).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information.
Allocation concealment (selection bias)	Unclear risk	Insufficient information.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Randomisation to Ginkgo biloba or placebo was made in a double blind manner.