Inclusion Criteria:

1. 18-70 years old (including 18 and 70 years old), regardless of gender;

2. Infection with new coronavirus pneumonia was confirmed by throat swab nucleic acid
test. Patients with severe and critical illness were clinically judged. The symptoms
of acute infection have been alleviated after treatment (at least 14 days after onset,
no fever for more than 3 days), and the disease is recovering Within three months;

3. CT examination of patients with multiple fibrotic shadows in both lungs;

4. Blood routine, liver, and kidney functions are within the controllable range: such as
the normal upper limit of plasma total bilirubin and creatinine ≤ 1.5 times; AST, ALT,
LDH ≤ 2 times the normal upper limit; sufficient hematopoietic function: such as white
blood cells ≥4.0 × 109 / L, platelets ≥100 × 109 / L;

5. Signed informed consent.

Exclusion Criteria:

1. Previous history of chronic bronchitis, emphysema, interstitial lung disease or
pulmonary heart disease;

2. Combining with other serious diseases: such as those who have suffered myocardial
infarction and uncontrollable diabetes within 6 months, and are considered unsuitable
to participate in the trial;

3. People with active peptic ulcer;

4. Patients during pregnancy and lactation

5. Patients with mental illness or others who cannot cooperate effectively;

6. Researcher judges uncomfortable to participate in trial