This is a multicenter, randomized, open Label, add-on study.

This is an add-on study of efficacy and safety of intravenous injection of Xiyanping injection in pediatric subjects with severe Influenza-Like Symptoms.

The purpose to determine the efficacy and safety of Oseltamivir Phosphate combined with or without Xiyanping injection in the treatment of severe Influenza-Like Symptoms. The study will enroll 72 Pediatric severe Influenza-Like Symptoms volunteers, who will be randomized into 2 groups (1:1 ratio): volunteers from the first group will receive Oseltamivir Phosphate and Xiyanping injection for severe Influenza; volunteers from the second group will receive Oseltamivir Phosphate for severe Influenza. Xiyanping injection will be administration as intravenous injection of 0.4mL/kg/day once daily for 7-10 days concomitantly with Oseltamivir Phosphate for severe Influenza-Like Symptoms.

Inclusion Criteria:

• Age between 3 and 6 years old;

• Clinical diagnosis of Severe Influenza with hospital treatment needed;

• Patients did not accept oseltamivir phosphate treatment or symptoms persisted for more than 3 days treatment;

  （1)Fever ≥ 39°C (tympanic temperature) for at least 3 days with Severe cough,sputum, blood stasis, or chest pain; （2）Combined pneumonia;

• The rapid viral antigen test of throat swab and nose swab results were positive;

• Guardians understood and assigned the informed consent;

Exclusion Criteria:

• Participants allergenic to XiYanPing injection, Andrographolide or Oseltamivir Phosphate;
• Creatinine clearance <80ml/min or received continuous renal replacement therapy (CRRT) test;
• Need extracorporeal membrane oxygenation (ECMO) at baseline;
• Glasgow Coma Rating Scale (GCS) score ≤ 9 points when dyspnea, altered consciousness, severe vomiting, or coma appeared at baseline;
• Crisis influenza Symptoms, such as respiratory failure, acute necrotizing encephalopathy, septic shock, multiple organ dysfunction and other serious clinical conditions requiring monitoring;
• Use of systemic steroids or other immunosuppressants;
• Participants with the following underlying diseases, including: heart disease (such as New York Heart Function Classification II-IV) or clinically significant arrhythmia (such as QTc ≥ 480ms), malignant tumor or other malignant diseases, autoimmune diseases; liver and kidney diseases ( ALT and AST ≥ 1.5 × ULN; Cr and BUN > 1.2 × ULN), blood diseases, nervous system diseases, immune system diseases and endocrine diseases, consciousness, speech, behavioral abnormalities caused by encephalitis / encephalopathy or limb paralysis, severe malnutrition, etc.
• Participants used Influenza virus vaccine within 3 months;
• Participants with drug dependence or with mental disorders within 1 year;
• Participants participated in other clinical research in the last 30 days;
• Any condition which would make the subject, in the opinion of the investigator or designee, not suitable for the study for any reason.

3 to 6 years old hospitalized patient