This multicentre, double-blind, randomized, placebo-controlled, parallel study was designed to evaluate the efficacy of combined oral lysine acetylsalicylate and metoclopramide (LAS-MCP) in the acute treatment of migraine attacks. A total of 266 patients, 18-65 years old, with two to six attacks of migraine with or without aura (IHS criteria) per month were included. The patients had to treat two migraine attacks with LAS-MCP (1620 mg lysine acetylsalicylate--the equivalent of 900 mg aspirin--combined with 10 mg metoclopramide) or placebo. The main outcome measure was headache relief (reduction in headache severity from grade 3 or 2--severe or moderate--to grade 1 or 0--mild or none) 2 h after treatment. LAS-MCP was superior to placebo for headache relief (56% vs 28%) and for the following secondary outcome measures: complete headache relief (18% vs 7%; p < 0.001), nausea (28% vs 44%; p < 0.001), vomiting (3% vs 11%; p = 0.001), use of rescue medication (47% vs 68%; p < 0.001), global efficacy judged as good or excellent (32% vs 14%; p < 0.001). The tolerability was considered as good in 94% of treated attacks in both groups. Combined oral lysine acetylsalicylate and metoclopramide is an effective and well-tolerated acute treatment of migraine attacks.