The new coronavirus (Sars-Cov-2) appeared in China in late 2019 and with it an intense search for effective pharmacological tools in the treatment of COVID-19. This virus can cause from mild symptoms, such as dry cough, fever and tiredness, to more severe symptoms, such as respiratory failure and systemic shock. Part of this problem is due to the increase in the neutrophil/lymphocyte ratio and serum levels of several inflammatory cytokines and chemokines. Other blood markers also deflagrate the inflammatory condition, among them C-reactive protein, ferritin and D dimers. Additionally, the history of chronic and/or acute hyperglycemia is an independent predictor for morbidity and mortality in patients with severe acute respiratory syndrome. In this pandemic scenario, numerous new and other drugs already available on the market have become therapeutic tools. Biguanide class drugs, classically used in the treatment of type 2 diabetes mellitus, received great notoriety for potentially useful systemic effects in the clinic, in cardiovascular level and against cancer. Some of their properties may be useful in the fight against Sars-Cov-2, such as the reduction of mRNA expression levels of inflammatory cytokines, chemokines and by the attenuation of NF-κB activation. These actions reduce the inflammatory response in the individual and the damage from a severe inflammatory response. Given the morbidity and mortality, partly attributed to the cardiovascular damage of the COVID-19, the objective of this work was to review the systemic effects of biguanides, as well as their therapeutic potential as an adjuvant.