Inclusion Criteria for Part I
1. Aged 18 to 65 years (including cut-off value), male or female;
2. Patients in the screening period met the following criteria:
* Rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) test positive;
* Pyrexial (axillary temperature ≥ 37.3 °C). If antipyretic drugs (including Chinese patent medicines) are taken, the axillary temperature should be ≥ 37.3 °C after administration(more than 4 hours);
* At least one Influenza viral infections-related General symptoms (Headache, Pyrexial or chills, muscle or Soreness of joint, Lassitude) score ≥ 2 points;
* At least one Influenza viral infections-related respiratory symptom (Coughing, Pharyngalgia, Nasal obstruction) score ≥ 2 points;
3. The first occurrence of influenza symptoms ≤ 48 hours from the time of patient randomization.
Inclusion Criteria for Part II
1. Aged 12 to 65 years (including cut-off value), male or female;
2. Patients in the screening period met the following criteria:
* Rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) test positive;
* Fever ≥ 37.3 °C(axillary temperature) at Screening. If antipyretic drugs (including Chinese patent medicines) are taken, the axillary temperature should be ≥ 37.3 °C after administration(more than 4 hours);
* At least one Influenza viral infections-related General symptoms (Headache, Pyrexial or chills, muscle or Soreness of joint, Lassitude) score ≥ 2 points;
* At least one Influenza viral infections-related respiratory symptom (Coughing, Pharyngalgia, Nasal obstruction) score ≥ 2 points;
3. The first occurrence of influenza symptoms ≤ 48 hours from the time of patient randomization.
Inclusion Criteria for Part I
1. Aged 18 to 65 years (including cut-off value), male or female;
2. Patients in the screening period met the following criteria:
* Rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) test positive;
* Pyrexial (axillary temperature ≥ 37.3 °C). If antipyretic drugs (including Chinese patent medicines) are taken, the axillary temperature should be ≥ 37.3 °C after administration(more than 4 hours);
* At least one Influenza viral infections-related General symptoms (Headache, Pyrexial or chills, muscle or Soreness of joint, Lassitude) score ≥ 2 points;
* At least one Influenza viral infections-related respiratory symptom (Coughing, Pharyngalgia, Nasal obstruction) score ≥ 2 points;
3. The first occurrence of influenza symptoms ≤ 48 hours from the time of patient randomization.
Inclusion Criteria for Part II
1\. Aged 12 to 65 years (including cut-off value), male or female; 2.Patients in the screening period met the following criteria:
* Rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) test positive;
* Fever ≥ 37.3 °C(axillary temperature) at Screening. If antipyretic drugs (including Chinese patent medicines) are taken, the axillary temperature should be ≥ 37.3 °C after administration(more than 4 hours);
* At least one Influenza viral infections-related General symptoms (Headache, Pyrexial or chills, muscle or Soreness of joint, Lassitude) score ≥ 2 points;
* At least one Influenza viral infections-related respiratory symptom (Coughing, Pharyngalgia, Nasal obstruction) score ≥ 2 points; 3.The first occurrence of influenza symptoms ≤ 48 hours from the time of patient randomization.
