inclusion criteria: - patients over 18 years of age - of both sexes - confirmed case of covid-19 (by rt-pcr) and ct less than 32 in the e - that they go to the er service due to covid symptoms, and that they voluntarily agree to participate in the study by written the informed consent - with at least 1 of the following symptoms: fever, headache, nausea, dyspnea, myalgia, vomiting, or diarrhea - with chest x-ray without pneumonia criteria - with so2> 90 - no history of allergic reaction to methylene blue - no history of treatment with medication with methylene blue negative interaction

inclusion criteria: - patients over 18 years of age - of both sexes - confirmed case of covid-19 (by rt-pcr) and ct less than 32 in the e - that they go to the er service due to covid symptoms, and that they voluntarily agree to participate in the study by written the informed consent - with at least 1 of the following symptoms: fever, headache, nausea, dyspnea, myalgia, vomiting, or diarrhea - with chest x-ray without pneumonia criteria - with so2> 90 - no history of allergic reaction to methylene blue - no history of treatment with medication with methylene blue negative interaction