The global pandemic caused by the novel coronavirus disease 2019 (COVID-19), for which there is no effective vaccine or treatment available yet, has led to a global health emergency. Despite a lack of clinical data, compelling evidence from the literature suggests that certain nutraceuticals (such as omega-3 fats, β-glucans, amino acids, probiotics, vitamins and minerals) and plant-based compounds derived from herbal extracts may potentially be used in the treatment of COVID-19. In the present review article, the benefits of such natural products in treating various respiratory complications are highlighted, and it is tentatively suggested that these benefits could be extrapolated to COVID-19. These natural compounds may not only modulate the immunity of a susceptible population, but may also pave the way towards the development of drugs which may be used to treat COVID-19. Although attention has recently focused on these compounds in this context, further clinical and experimental studies are required to validate their efficacy. It is thus suggested that the in vitro and in vivo evaluation of these compounds be carried out as soon as possible, in order to counteract the ongoing increase in the number of cases of COVID-19. Contents 1. Introduction 2. Therapeutic benefits of nutraceuticals for respiratory complications 3. Therapeutic benefits of herbal extracts for respiratory complications 4. Conclusion Prevention and treatment of COVID-19. As of August 5, 2020, no vaccine or successful treatment for COVID-19 has been reported and only supportive care, personal protection, early diagnosis and isolation are available to reduce the spread and severity of the infection (5). Huang et al (6) reported that patients with COVID-19 develop acute respiratory distress syndrome, followed by anemia, acute heart injuries and secondary infections. Empirical therapy with antibiotics (including cephalosporins, azithromycin, vancomycin, quinolones, tigecycline and carbapenems), antivirals (including lopinavir, ritonavir, remdesivir and oseltamivir) and corticosteroids (including dexamethasone and methylprednisolone) has thus been used for the treatment of patients with COVID-19 (7). The clinical efficacy of all of these treatments, however, warrants further confirmation. Potential agents with which to combat COVID-19. Research proposals and clinical trials have suggested that some treatments, including supplements and phytochemicals, have the potential to help fight coronavirus infection. A recent study suggested that the risk of becoming infected could be reduced by vitamin D3 supplementation. Serum concentrations >40-60 ng/ml (100-150 nmol/l) were suggested to be
