This study was conducted in a randomized, double-blind, placebo-controlled, multicenter clinical trial design. Two groups were designed, the experimental group and the placebo control group. Patients in both groups received basic treatment with vitamin C effervescent tablets. Tanreqing capsule was added to basic treatment in the experimental group, and placebo was added to basic treatment in the control group. The treatment course was 7 days, and the observation period was set to 7 days, with a daily visit.

The purpose of this study was to evaluate the efficacy and safety of Tanreqing capsule in the treatment of mild and common COVID-19. The trial was a randomized, double-blind, placebo-controlled, multicenter clinical trial design. A total of 480 patients were divided into 2 groups: experimental group and control group 3:1. Patients in both groups received basic treatment with vitamin C effervescent tablets. Tanreqing capsule was added to basic treatment in the experimental group, and placebo was added to basic treatment in the control group. The treatment course was 7 days, and the observation period was set to 7 days, with a daily visit.

Inclusion Criteria:

1. According to the Diagnosis and Treatment Plan for Pneumonia Infected by novel coronavirus (Trial Version 9), those who are in line with the diagnosis of novel coronavirus pneumonia and whose clinical classification is light and ordinary；
2. Aged greater than 18, with no gender limitation;
3. Symptom score greater than or equal 3 points;
4. Voluntarily accept the drug treatment and sign the informed consent.

Exclusion Criteria:

1. Patients with severe primary respiratory diseases or other pathogenic microbial pneumonia that needs to be differentiated from COVID-19;
2. immune deficiency disease, or use of immunosuppressants or glucocorticoids in the last 3 months;
3. pregnant and lactating women;
4. People with allergic constitution (allergic to more than two drugs or food or known allergic to the drug used in this study);
5. mentally ill persons or persons without self-awareness;
6. Patients whose expected survival time from screening is not more than 48 hours; (7) those who have been intubated or mechanically ventilated at the time of screening;

(8) In patients with serious primary diseases of heart, brain, liver and kidney, ALT and AST were 1.5 times higher than the upper limit of normal value; (9) Other conditions that the investigator considers inappropriate for clinical trial participation.