Study aim: The effect of spirulina platensis supplementation on disease severity and mortality in patients with coronavirus. Design: This clinical trial has parallel intervention and control group, open-label, randomized, multicenter, phase 3 on 240 patients. Random Allocation Software was used for randomization. Settings and conduct: The present study is an open-label clinical trial. The target population is patients hospitalized in the coronavirus ward of Ziaeian Hospital and Baharloo Hospital. Participants/Inclusion and exclusion criteria: Patients with coronavirus. Inclusion criteria 1- Male and female patients, age ≥18. 2- The patient is stable in condition and does not need resuscitation. 3- Signed informed consent form. 4- Definitive/clinical diagnosis of coronavirus. ... Exclusion criteria 1- Pregnancy or lactation. 2- Any history of drug allergy. 3- Active, clinically significant chronic illness or human immunodeficiency virus disease. 4- Significant organ dysfunctions such as renal failure, liver dysfunction, CHF, or serious and unstable cardiac condition. ... Intervention groups: Based on the entry criteria, patients who are eligible to enter the study are randomly divided into two intervention and control groups using the block randomization method. After obtaining consent from the patients, the intervention group will receive 15/2 g spirulina platensis algae powder daily. Main outcome variables: Reducing the severity of the disease and its mortality.