To evaluate the safety and pharmacokinetics of GV-971 capsules after oral a single or multiple doses of 900 mg, 1200 mg and 1500 mg in healthy subjects.

Inclusion Criteria:

1. Healthy subjects;
2. Age：≥18 and ≤40 on the date signing informed consent;
3. Body mass index (BMI): 19-26 kg/m2 and the weight ≥50 kg for male and ≥45 kg for female；
4. Subjects are able to understand the study procedures and methods, and willing to strictly comply with the protocol and give written informed consent.

Exclusion Criteria:

1. Subjects may be allergic to GV-971 in the opinion of the investigator;
2. With diseases which could impact on the absorption, distribution, metabolism and excretion (ADME) of study drugs or protocol adherence in the opinion of the investigator (such medical disorder/disease may relate to cardiovascular, liver, kidney, digestive, immune, blood, endocrine, metabolic, cancer, neuropsychiatric,etc );
3. Blood donation of ≥400 mL or severe blood lose and the volume of blood loss ≥400 mL within 12 weeks prior to screening;
4. Participation in any investigational drug or medical instrument study within 3 months prior to screening;
5. Use of any prescription medicine or herbal remedy, over the counter medication or dietary supplements such as vitamin, calcium within 2 weeks prior to screening;
6. Smoking more than 10 cigarettes a day, drugs or alcohol abuse within 6 months prior to screening;
7. Use of heparin, alginic sodium diester , mannose ester within 4 weeks prior to screening；
8. Clinically significant abnormalities in physical examination and laboratory test results or 12-lead ECG, etc. in screening;
9. Clinically significant abnormalities in Chest X-ray or abdominal B-ultrasound examination;
10. Positive seurology screen for Hepatitis B( HBsAg), Hepatitis C(HCV), HIV and USR unheated serum reagin test;
11. Vegetarian or person with dietary restrictions;
12. Subjects able to father a child are unwilling to use highly effective physical form of birth control from the trial period until 3 months after the completion of study;
13. Any other reasons that the subject is not eligible for participation in the study in the opinion of the investigator.