This is a randomized, double-blind, placebo-controlled, adaptive clinical trial, which will assess the effect of DanshenDuofensuanyan[Danshen (a kind of Chinese herbal drug) extract] treatment on Lipoprotein associated phospholipase A2 level in patients with stable angina pectoris.

Inclusion Criteria:

1. Age:18 years-75 years;

2. Written informed consent;

3. Patients with a clinical diagnosis of chronic stable angina, which fulfil one of the following conditions:

   1. Symptoms that support the diagnosis of chronic angina and/or a history of an abnormal exercise response limited by angina and/or electrocardiograph (ECG) changes
   2. a history of myocardial infarction and ST-T changes,
   3. stenosis of more than 50 % in at least one major epicardial coronary artery, as shown by coronary angiography or computed tomography angiography,
   4. Coronary heart disease confirmed by radionuclide angiocardiography;

4. Patients with moderate angina pectoris, which is defined as Grade II or III on the Canadian Cardiovascular Society Angina Grading Scale.

Exclusion Criteria:

1. Patients with severe complications that would complicate the condition, as assessed by the investigator, including liver or renal dysfunction, severe cardiopulmonary dysfunction, pulmonary hypertension, chronic obstructive pulmonary disease, a history of epilepsy or cerebral haemorrhage.
2. Patients who were angina-free during the run-in period without taking any drug.
3. Patients who experienced myocardial infarction or who were classified as Grade IV on the Canadian Cardiovascular Society Angina Grading Scale within the preceding 3 months.
4. Patients with chest pain that is caused by any other disease (e.g., acute myocardial infarction, severe neurosis, menopausal syndrome or hyperthyroidism).
5. Patients with a history of drug-induced bleeding or a history of bleeding caused by warfarin.
6. Patients with a history of haematopoietic disorder.
7. Patients who have had surgery within the previous 4 weeks or who have a haemorrhagic tendency.
8. Women who are pregnant or lactating or who have a positive pregnancy test, or women who have a menstrual period at baseline.
9. Patients who are participating in other trials or who have participated in other trials within the past 3 months.
10. Patients with a history of allergy or with a known or suspected allergy to the study drug.
11. Patients with a known or suspected history of alcohol or drug abuse within the past 2 years.
12. Patients with a mental disorder.
13. Family members or relatives of the study centre staff.
14. Inability to adhere to study procedures

We could provide individual participant data without leaking the patients' personal information if needed.