en عمومى General پژوهشي Research <p><strong>Background:</strong> COVID-19 became widespread in 2019 worldwide and affected everyone. Even though it was a disease caused by a new strain of coronavirus with severe symptoms, some drugs could be effective in its treatment. It seems that methylene blue (MB), a drug for treating methemoglobinemia, can be a useful COVID-19 treatment.</p> <p><strong>Methods:</strong> Overall, 60 COVID-19 patients with an O₂ saturation of less than 85% and with no underlying diseases were chosen and included in this study. The patients were divided into the placebo control group (n=30) and the MB-treated group (n=30) and received 1 mg/kg of MB for 4 days. Some serum parameters were measured before and after 4 days of treatment. In addition, the O₂ saturation was measured every 12 hours. Then, the results were compared with each other.</p> <p><strong>Results:</strong> MB decreased the serum C-reactive protein (<em>P</em>=0.14), lactate dehydrogenase (<em>P</em>=0.08), and creatinine (<em>P</em>=0.12) in the COVID-19 patients non-significantly and increased the serum aspartate aminotransferase (<em>P</em>=0.40) and alanine aminotransferase (<em>P</em>=0.36) parameters in comparison with the control placebo group. However, it had no significant effect on O₂ saturation (<em>P</em>=0.52) in COVID-19 patients.</p> <p><strong>Conclusion:</strong> MB, a specific drug for treating methemoglobinemia, had no significant effect on COVID-19 patients.</p> COVID-19, Methylene blue, O2 saturation 87 91 http://ajpr1.umsha.ac.ir/browse.php?a_code=A-10-2-18&slc_lang=en&sid=1 Javad Saffari-Chaleshtori 1003194753284600127 1003194753284600127 Yes Department of Clinical Biochemistry, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran Masoud Hafizi 1003194753284600128 1003194753284600128 No Clinical Research Development Unit, Hajar Hospital, Shahrekord University of Medical Sciences, Shahrekord, Iran Ali Baradaran 1003194753284600129 1003194753284600129 No Clinical Research Development Unit, Hajar Hospital, Shahrekord University of Medical Sciences, Shahrekord, Iran Keyhan Ghatreh-Samani 1003194753284600130 1003194753284600130 No Clinical Biochemistry Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran Roohollah Mohseni 1003194753284600131 1003194753284600131 No Clinical Biochemistry Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran Akbar Soleimani dr.akbarsoleimani@yahoo.com 1003194753284600132 1003194753284600132 No Clinical Research Development Unit, Hajar Hospital, Shahrekord University of Medical Sciences, Shahrekord, Iran