Background: Compound edaravone is a novel neuroprotective agent that comprised edaravone and (+)-borneol, a food additive with an anti-inflammatory effect in animal ischaemic stroke models. This study aims to assess the safety and efficacy of compound edaravone compared with edaravone in treating patients with acute ischaemic stroke (AIS). Methods: In this multicentre, randomised, double-blind, multiple-dose, active-controlled, phase II clinical trial, patients with AIS within 48 hours after stroke onset were randomly assigned (1:1:1:1) to low-dose (12.5 mg), medium-dose (37.5 mg) or high-dose (62.5 mg) compound edaravone groups, and an active control group with edaravone (30 mg) by 30 min intravenous infusion every 12 hours, for 14 consecutive days. The primary efficacy outcome was the proportion of modified Rankin Scale (mRS)score ≤1 at 90 days and National Institutes of Health Stroke Scale (NIHSS) score change from baseline to 14 days after randomisation. The safety outcome included any adverse event during 90 days after treatment. Results: Of 385 patients included in the efficacy analysis, 94 were randomised to low-dose group, 97 to medium-dose group, 98 to high-dose group and 96 to the control group. No significant difference was observed among the four groups on mRS score (mRS ≤1, p=0.4054) at 90 days or NIHSS score change at 14 days (p=0.6799). However, a numerically higher percentage of patients with mRSscore ≤1 at 90 days in the medium-dose (69.39%) and high-dose (65.63%) groups was observed than in the control group (60.64%). No significant difference in severe adverse events was found among the four groups (p=0.3815). Conclusions: Compared with edaravone alone, compound edaravone was safe and well tolerated at all doses, although no significant improvement in functional outcomes was observed at 90days. Trial registration number: NCT01929096. © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.