Rejali 2004.

Study characteristics
Methods	A 2‐armed (Gingko biloba and placebo), parallel‐group randomised controlled trial with 12 weeks duration of treatment and 12 weeks duration of follow‐up
Participants	Location: Airdrie, UK Setting: single‐centre study, Department of Otolaryngology, Monklands Hospital Sample size: Number randomised: 33 in Ginkgo biloba group and 33 in placebo group Number completed: 31 in Ginkgo biloba group and 29 in placebo group Participant baseline characteristics: Age (mean (SD) years): 60 (11.4) in Ginkgo biloba group versus 59 (10.4) in placebo group Gender (male/female, n): 17/14 in Ginkgo biloba group versus 17/12 in placebo group Other characteristics: baseline tinnitus symptom severity measured with THI was 37.5 (SD 20.5) in the intervention group and 50.7 (SD 23.3) in the placebo group. Mean tinnitus duration was 4.4 years (SD 4.6) in the intervention group and 6 years (SD 4.9) in the placebo group. Tinnitus was constant in 87% of participants in the intervention group and 90% in the placebo group and intermittent in 13% and 10% of participants, respectively. Tinnitus was unilateral in 39% of participants in the intervention group and 31% of participants in the placebo group. Averaged air‐conduction threshold at 0.5 kHz, 1 kHz, 2 kHz and 4 kHz for both ears was 26.8 dB in the intervention group and 35.2 dB in the placebo group. Inclusion criteria: adult patients recruited from general otolaryngology outpatient clinics with tinnitus as their only or main presenting complaint Exclusion criteria: patients with active middle or external ear disease, known hypersensitivity to Ginkgo biloba and pregnant patients, and patients already on Ginkgo biloba, warfarin or with bleeding diatheses were excluded from the study
Interventions	Intervention group: Ginkgo biloba tablets, 120 mg once a day, 12 weeks Comparator group: placebo tablets, 1 tablet a day, 12 weeks Use of additional interventions: none reported
Outcomes	Primary outcome: change in tinnitus symptom severity measured with THI at 12 weeks Secondary outcomes: change in handicap caused by otolaryngological disease measured with Glasgow Health Status Inventory (GHSI) at 12 weeks; change in hearing determined by averaging air conduction thresholds for both ears at 0.5 kHz, 1 kHz, 2 kHz and 4 kHz at 12 weeks; adverse effects
Funding sources	Quote: "We acknowledge Lamberts Healthcare for the supply of G. biloba and placebo medication."
Declarations of interest	No information provided
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was carried out by an independent third party using a card from bag system.
Allocation concealment (selection bias)	Low risk	Randomisation was carried out by an independent third party using a card from bag system.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The study was double‐blind. The patients received either 120 mg once daily sustained release formulation of Ginkgo biloba or placebo (all tablets provided by Lambert’s Health Care, TunbridgeWells, UK) for 12 weeks.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Information not reported in the manuscript.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Small dropout (3 participants: 1 in intervention and 2 in placebo group); reasons for dropout explained.
Selective reporting (reporting bias)	Low risk	All outcomes reported.
Other bias	Unclear risk	No prospective protocol available. No declarations of interest reported. Baseline tinnitus severity higher in the control group.