The goal of this clinical trial is to learn if Shengmai liquid works to treat Long Covid fatigue. It will also learn about the safety of Shengmai liquid. The main questions it aims to answer are:

• Dose the Shengmai liquid will reduce the level of fatigue in the participants and reduce the fatigue scale score of the participants?
• Dose the Shengmai liquid will reduce the level of anxiety and depression in the participants and improve the sleep quality and quality of life of the participants Researchers will compare Shengmai oral liquid to a placebo (a look-alike substance that contains no drug) to see if Shengmai liquid works to treat Long Covid fatigue.

Participants will:

• Take Shengmai liquid or a placebo every day for 8 weeks.
• Visit the clinic once every 4 weeks for check up and test. There are a total of two telephone follow-ups, one follow-up 15 days after the treatment starts and another follow-up 30 days after the treatment ends.
• Participants' medication responses and scale scores will be recorded.

Inclusion Criteria:

• Aged between 18 and 75 years;
• Meet the above diagnostic criteria;
• Meet the traditional Chinese medicine syndrome diagnostic criteria;
• Consent and sign the informed consent form

Exclusion Criteria:

• Currently in need of or expected to require high-flow oxygen therapy, positive pressure ventilation, invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO) and other advanced respiratory support measures;
• Have a known history of active liver disease (excluding non-alcoholic fatty liver changes), including active hepatitis B or C infection, primary biliary cirrhosis, Child-Pugh class B or C liver function impairment, or acute liver failure. Liver function at screening shows any of the following: serum alanine aminotransferase (ALT) >3× the upper limit of normal (ULN); serum aspartate aminotransferase (AST) >3×ULN; serum bilirubin >2×ULN;
• Undergoing dialysis treatment, or known to have moderate to severe renal impairment (i.e., an estimated glomerular filtration rate (eGFR) value calculated based on serum creatinine using the CKD-EPI formula ≤45 mL/min/1.73 m² within 6 months before screening);
• Moderate to severe congestive heart failure within 6 months before screening (according to the New York Heart Association classification criteria, with cardiac function class III or IV), experienced a stroke, myocardial infarction, or coronary artery stent implantation; or have uncontrolled hypertension (defined as systolic blood pressure exceeding 160 mmHg or diastolic blood pressure exceeding 100 mmHg, with relevant records). Significant or clinically relevant electrocardiogram abnormalities, such as second-degree type II atrioventricular block, left bundle branch block, etc.;
• Suffered from influenza A, influenza B, or other infectious diseases within 3 months before screening;
• Have/ever had severe neurological diseases (epilepsy, convulsions, or seizures) or mental illness, or have a family history of mental illness;
• Pregnant or breastfeeding. Women who are breastfeeding or have a positive pregnancy test before taking the medication;
• History of malignant tumors within 5 years before screening, with existing and progressing tumors, and patients who are expected to need treatment during the study period;
• Have chronic fatigue syndrome or autoimmune diseases (such as rheumatoid arthritis, systemic lupus erythematosus, etc.);
• Known allergy to any component of the study drug;
• Diseases judged by the investigator to be unsuitable for participation in this study;
• Taken traditional Chinese medicine containing Codonopsis pilosula, Ophiopogon japonicus, Schisandra chinensis, or Astragalus membranaceus within 2 weeks before screening;
• Participating in other drug or medical device-related studies at the same time