**3.1 Echinacea in COVID-19**

Echinacea has antiviral and immunomodulatory effects that seems to be promising against COVID-19 [13, 26]. Several studies have investigated the benefits of echinacea in treating and preventing respiratory tract infections such as the common cold, but not for other health purposes [27]. No studies have yet been completed on echinacea and COVID-19 [28]. A meta-analysis including 17 clinical trials found that echinacea is safe and effective in preventing or treating viral infections. In a separate analysis including 12 clinical trials, echinacea showed to decrease or not change pro-inflammatory cytokines associated with cytokine storm (IL-6, IL-1β, and TNF-α) and increase or not change anti-inflammatory or immunestimulatory cytokines (IL-10, IL-2, IL-8, IL-3, and IFN-γ). These effects are beneficial during infections since immune stimulatory and anti-inflammatory effects are needed but pro-inflammatory cytokines can aggravate the disease. Adverse events were mild with the most common reported being insomnia, gastrointestinal, and anxiety. One case of serious erythema was reported. Most studies included healthy participants and echinacea dose and method of extraction were quite variable making it difficult to evaluate safety in patients with comorbidities [28].
