Unstable angina (UA)/non-ST-segment elevation myocardial infarction (NSTEMI) is associated with an increased risk of cardiac death and an efficacious drug with few side effects is necessary. The study aimed to evaluate the effects of Bulbus allii macrostemi (B. macrostemi) on UA/NSTEMI patients as well as to elucidate possible mechanisms. 79 patients were randomly divided into two groups: the trial group received B. macrostemi plus baseline therapy, the control group was given placebo plus baseline therapy. The trial lasted 8 weeks. The evaluation involved main clinical symptoms, changes of electrocardiogram and biochemical examination. After treatment, the trial group showed more significant improvement on clinical manifestation. The plasma oxidized low-density lipoprotein (ox-LDL) level decreased significantly in the trial group (p < 0.01); the plasminogen activator inhibitor-1 (PAI-1) level decreased in both groups and it decreased more significantly in the trial group (p < 0.01). In contrast, the activity of plasminogen (PLG) increased in both groups and the change was more marked in the trial group (p < 0.01). The results suggested that B. macrostemi combined with baseline therapy could improve clinical symptoms of UA/NSTEMI patients by decreasing the ox-LDL and PAI-1 levels and enhancing the activity of PLG.