Study aim: A study on melatonin and Vitamin C and zinc efficacy in patients with COVID19 hospitalized in intensive care unit of Semnan Kowsar Hopsital Design: Clinical trial with control group, Randomized, Single-center, Sample size 30 people (2 groups of 15 people). Settings and conduct: Kowsar Hospital in Semnan. In addition to national protocol medications, patients receive 40 mg of melatonin (2 5 mg tablets every 6 hours) via NG tube. Patients will also receive 2 grams of ascorbic acid per day at 5% dextrose every 6 hours, plus 220 mg of sulfate every 6 hours. The duration of treatment with this medication regimen will be 5 days. Participants/Inclusion and exclusion criteria: Inclusion criteria: Patients with Covid 19; Conscious consent of the patient. Exclusion criteria: Malignant diseases; Severe renal, hepatic failure; History of drug allergy. Intervention groups: Intervention group: In addition to national protocol medications, patients receive 40 mg of melatonin (2 5 mg tablets every 6 hours) via NG tube. Patients will also receive 2 grams of ascorbic acid per day at 5% dextrose every 6 hours, plus 220 mg of sulfate every 6 hours. The duration of treatment with this medication regimen will be 10 days. Control group: Patients are treated according to national protocol. Only for comparison with intervention group. Main outcome variables: Number of breaths per minute; The rate of decline of lung infection; The course of the disease; Heart rate.