There is a growing body of evidence that the poor outcome of novel coronavirus infection (COVID-19) is related not only to pneumonia but also to thrombotic complications. Among the putative mechanisms accounting for vascular disease, the overproduction of reactive oxygen species (ROS) could play a role. Thus, ROS formation is involved in the process of platelet and clotting activation and could be implicated in the thrombotic process of COVID-19. Studies performed in COVID-19 patients showed over-activation of NOX2 in cells deputed to ROS formation and implicated in thrombosis such as leucocytes and platelets. Furthermore, several types of antioxidants such as albumin and vitamin C and E are lowered in COVID-19 suggesting an imbalance between ROS over-production and low antioxidant status as a mechanism eliciting changes of redox status. However, interventional studies with antioxidants provided inconclusive results, therefore further study is necessary to assess the efficacy of this treatment in COVID-19.