Banlangen Granules Anti-seasonal Influenza Study: a Randomized, Double Blind, Positive and Placebo Controlled，Clinical Study.

Inclusion criteria:

1. Patients have confirmed influenza A(H1N1,H3N2) or influenza B virus infection by real time PCR
2. age between 18-65 years old
3. axillary temperature ≥38ºC and with at least two constitutional symptoms (headache, chill, myalgia ，or fatigue) and one respiratory symptom (cough ，sore throat,or coryza) .
4. Illness onset had to be within 36 hours, and informed consent was obtained.

Exclusion criteria:

1. age younger than 18 or older than 65 years old.

2. patients confirmed with bronchitis, pneumonia,pleural effusion and interstitial lung disease by Chest imaging (chest X-ray or CT) .

3. Blood routine screening tests shows numeration of leukocyte 10.0×109/L or Neutrophil percentage ≥80%.

4. Those have got suppurative tonsillitis or cough purulent sputum.

5. Those with underling primary disorders, such as hematological disease, chronic obstructive pulmonary disease（FEV1/FVC<70％，FEV1/ predicated value<50％； or respiratory failure or right heart failure）， hepatic disease（ALT or AST≥triple ULN）, renal disease（Serum Creatinine>2mg/dL）,chronic congestive heart failure( NYHA Ⅲ-IV)

6. Patient is allergic to the study medication(s). 8. Women who are pregnant or may possibly become pregnant or are lactating with a positive urine pregnant test, obesity (abody mass index (BMI) of 25 kg/m2 or more).