To evaluate the safety, tolerability and pharmacokinetics of HEC53856 after single or multiple oral administration, as well as the food effect on the pharmacokinetics, in healthy non-elderly subjects.

This is a Phase I, Single Center, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Tolerability and Pharmacokinetics of HEC53856 capsule in Healthy Adult Subjects. The study consists of three parts, single dose ascending, multiple dose ascending and food effect testing. Within each part participants will be randomized to either drug or placebo.

Inclusion Criteria:

• healthy volunteers
• age: 18-45 years old(18 and 45 included).
• B.W. male> 50kg, female> 45kg, BMI - 18-28 kg/m^2
• females must not be pregnant and males and females must agree to use contraception during the study.
• able to give informed consent and comply with protocol.
• physical examination and vital signs without clinically significant abnormalities.
• agree to use contraceptive methods after informed consent acquisition through 6 months after the last administration of the study drug.

Exclusion Criteria:

• history or presence of severe gastrointestinal or systemic disorders (e.g. respiratory, endocrine, immunological, dermatological, neurological, psychiatric, renal, hepatic disease etc.)
• history or presence of significant alcoholism or drug abuse within past 5 years
• smokers, who smoke more than 5 cigarettes per day within past 3 months
• heavy drinker, namely alcohol consumption are 14 units per week (1 unit = 285 mL of beer, or 25 mL of strong wine, or 100 mL of grape wine);
• donated blood or massive blood loss within 3 months before screening (>450 mL）
• have any disease that increases the risk of bleeding or thrombus, such as acute gastritis or stomach and duodenal ulcers;
• clinically significant laboratory findings during screening
• history or presence of clinically significant ECG abnormalities
• participated in drug research study within past 3 months
• used over-the-counter/ prescription/ herbal medications/ supplements within past 14 days.
• Strenuous activity (as assessed by the investigator) is prohibited from 2 weeks prior to admission until discharge from the unit.
• female in pregnancy or lactation.
• viral hepatitis（including CHB and CHC）and positive test result of anti-HIV Ab or syphilis.
• the investigator believes that the one should not be included