Based on our preclinical data showing a potential accelerating effect of acetylsalicylic acid (ASA) in combination with fluoxetine in an animal model of depression, we examined the effect of ASA augmentation therapy on selective reuptake inhibitors (SSRI) in major depressed non-responder patients. Twenty-four non-responder patients having received at least 4 weeks of an adequate SSRI treatment were included in a pilot open-label study. Participants were treated openly during 4 weeks with 160 mg/day ASA in addition to their current antidepressant treatment. The combination SSRI-ASA was associated with a response rate of 52.4%. Remission was achieved in 43% of the total sample and 82% of the responder sample. In the responder group, a significant improvement was observed within week 1 (mean Hamilton Depression Rating Scale-21 items at day 0=29.3+/-4.5, at day 7=14.0+/-4.1; P<0.0001) and remained sustained until day 28. Despite limitations due to the open nature of this study, our preliminary results confirm our preclinical findings and are in favour of an accelerating effect of ASA in combination with SSRIs in the treatment of major depression. Potential physiological and biochemical mechanisms may involve an anti-inflammatory and/or neurotrophic effect.