Evaluations were done comparing C-reactive protein (CRP) concentrations and ROX score (defined as the ratio of oxygen saturation measured by pulse oximetry/FiO2 to respiratory rate) between a control group constituted by COVID-19 patients receiving standard medication and the group receiving xanthines from day 1 to day 4 of therapy, and results showed an increase in the ROX score (mean: 2.9) and a decrease in CRP (mean: −0.7) and mortality (24%) for the theophylline/pentoxifylline group. Here, CRP is linked to COVID-19.