This is a placebo-controlled, randomized, double-blind, multiple dose study that evaluated the safety, tolerability, and changes in indicators of immune function of Korean Red Ginseng Extract in Vietnamese healthy subjects following oral administration of multiple dose of Korean Red Ginseng Extract as hard capsules or placebo to healthy adult men.

Inclusion Criteria:

• Healthy adult male or female aged 20 to 65 years, inclusive at the time of informed consent
• Have not any abnormalities of vital signs (temperature, systolic blood pressure (SBP) and diastolic blood pressure (DBP) and pulse rate), physical examinations, clinical laboratory tests (hematology, chemistry, and urinalysis).
• Ability and willingness to provide written informed consent and to comply with the requirements of the protocol.
• Peripheral white blood cells in the range of 3000 - 10,000/μL
• Subjects with a history of being infected with COVID-19 within 12 months according to the diagnostic criteria of the Ministry of Health at the time of infection

Exclusion Criteria:

• Pregnancy or lactation
• For subjects of reproductive potential, a positive result from a serum pregnancy test at screening, or not willing to use reliable means of contraception
• Evidence of clinically significant acute or chronic hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psych, neurological, or neoplastic diseases (however, at the discretion of the principal investigator, subjects may also be considered)
• Uncontrolled hypertension (SBP ≥160 mmHg and/or DBP ≥100 mmHg, measured following at least 10 mins of rest)
• Uncontrolled diabetes (fasting glucose level above 126 mg/dL or diabetic patients who have initial treatment with antidiabetic drugs for ≤ 3 months)
• Aspartate aminotransferase or alanine aminotransferase >=3.0 × upper limit of normal
• Serum creatinine level > 2,4 mg/dL for male and > 1,8 mg/dL for female
• Use of medications and dietary supplements that can affect immunity within 2 weeks before screening
• Those who complain of severe gastrointestinal symptoms such as heartburn and indigestion
• History of sensitivity or allergy to investigational product-related foods
• Plan to participate in other research while participating in this research
• Subject who, in the judgment of the Investigator, is likely to be non-compliant or uncooperative during the study.
• Failure of follow instructions for discontinuing immune-affecting dietary supplements during the wash-out period prior to trial participation