Methods	Multicentre, randomised, double-blind, three-arm, parallel-group, double-dummy. Single oral dose Medication taken when migraine headache pain of moderate or severe intensity Assessments at 0, 0.5, 1, 1.5, 2 and 24 hours. If pain not controlled, participants asked to wait 2 hours before taking rescue medication
Participants	Aged 18-65 years, meeting IHS criteria for migraine with and without aura. At least 12-month history of migraine, with one to six attacks per month N = 433 M = 66, F = 367 Mean age 42 years
Interventions	Effervescent acetylsalicylic acid 1000 mg, n = 146 Sumatriptan 50 mg, n = 135 Placebo, n = 152
Outcomes	Headache relief at 1 and 2 hours Pain-free at 2 hours 24-hour sustained relief Adverse events Remission of associated symptoms: nausea, photophobia, phonophobia Overall impression of study medication Need for rescue medication
Notes	Oxford Quality Score: R2, DB2, W1. Total = 5.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	“Computer-generated randomisation list”
Allocation concealment?	Unclear	Not described
Blinding? All outcomes	Yes	“Matching effervescent or tablet placebo”