Efficacy and Safety of Yangxue Qingnao Pills in the Treatment of Mild to Moderate Alzheimer's Disease

Inclusion Criteria: Patients, Chinese speaking, in both gender are eligible to be included in the study only if they meet all of the following criteria: 1. Meets NIA/AA core clinical criteria for probable AD; 2. The body weight is between 45-90kg; 3. Aged ≥ 65 and ≤ 85 years old; 4. Mild to moderate stage of AD, defined as( MMSE score of 15 through 26) at baseline; 5. Has had an MRI scan performed at baseline that has confirmed with a diagnosis of AD, Medial temporal atrophy scale (MTA) is used for routine assessment of the medial temporal lobe, and the MTA score need ≥1.5 (adjusted by age: 65-74 years ≥ 1.5 points, 75-84 years old ≥ 2.0 points); 6. Has a PIB-PET scan or CSF result consistent with the presence of amyloid pathology at screening; 7. And the patients must have adequate vision and hearing to participate in study assessments; has normal swallowing function, and can complete the medication; 8. Have a stable caregiver; 9. Can read simple articles and write simple sentences; 10. Informed consent, signed informed consent by legal guardian. Exclusion Criteria: Patients who confirmed with any of the following excluding criteria conditions were not enrolled for the study: 1. Early-onset Alzheimer disease (oneset at \<65 years of age) and moderate to severe AD dementia (MMSE 14-0); 2. Evidence of other reasons caused cognitive impairment, like vascular dementia, frontotemporal dementia, Parkinson's disease dementia, Lewy body dementia, Huntington's disease, subdural hematoma, communicating hydrocephalus, brain tumor, thyroid disease, vitamin deficiency Or other diseases that may cause cognitive impairment, or serious brain infections (including neurosyphilis, meningitis or encephalitis), etc.; 3. There are unstable mental disorders, including major depression (HAMD≥17), severe anxiety disorder (HAMA≥12 points), bipolar disorder, schizophrenia, etc.; 4. History of drug or alcohol abuse in the past 5 years; 5. Other uncontrolled chronic illnesses, such as severe arrhythmia (ventricular rate \<60 beats/min or \>100 beats/min, or patients with myocardial infarction within 3 months before participating in the trial, or severe heart failure (NY classification III and IV), or severe abnormal blood pressure, systolic blood pressure ≤90mmHg or ≥180mmHg; 6. Severe liver or kidney dysfunction (alanine aminotransferase or aspartate transaminase was more than 1.5 times the upper limit of normal, or serum creatinine was more than the upper limit of normal); 7. A history of taking cholinesterase inhibitors, memantine, or proprietary Chinese medicines with clear nootropic effects within the past 1 month; 8. Has received medications that affect the central nervous system (CNS), except treatments for AD for less than 4 weeks; that is, doses of chronic medications that affect the CNS should be stable for at least 4 weeks; 9. One of the following manifestations on cranial MRI:\> 4 cerebral microhemorrhages, evidence of a prior macrohemorrhage, \> 3 lacunar infarcts over 10 mm each, any cortical infarct over 10 mm, or any other clinically significant finding (e.g., any lesion that may account for their cognitive impairment, including but not limited to brain tumor, severe white matter disease with a rating of 3 on the Fazekas scale for WM lesions ,arteriovenous malformation, cavernous hemangioma, or any infarct in a strategic subcortical location); 10. History of hypersensitivity to the treatment drugs; 11. Participate in other clinical study within the last 30 days; 12. Has metal (ferromagnetic) implants, or a cardiac pacemaker and other conditions that could not undergo MRI scan; 13. or other conditions that, in the investigator's opinion, could interfere with the analyses of safety and efficacy in this study.