This is a randomized, double blind, placebo controlled study of intracoronary cocktail injection combined with thrombus aspiration versus thrombus aspiration alone in ST-elevation myocardial infarction patients treated with primary angioplasty. Patients with STEMI will be randomized into the cocktail group or the control group. Patients in the cocktail group will receive cocktail injection combined with thrombus aspiration. Patients in the control group will receive thrombus aspiration alone. The primary outcome of the cocktail I study is the composite of death, myocardial infarction or class IV heart failure within 1 year. The secondary outcome of the cocktail I study include slow reflow/no reflow during PCI, left ventricular function, quality of life, stroke or life-threatening bleeding within 1 year.