Atherosclerosis is plaque formation in the arteries which will further develop into plaque, narrowing and shocking the artery. Continuous plaque formation leads to acute and chronic inflammation and soon develop into atherosclerosis. A combination of herbs in form of drink, consist of tanjung leaves (Mimusops elengi L.), starfruit leaves (Averrhoa carambola L.), and temulawak (Curcuma xanthorrhiza R.) is empirically believed to be anti-atherosclerotic; because it contains quercetin that initiate anti-inflammatory activity. Quercetin concentration test was conducted using an aluminum chloride colorimetric assay with variations in particle size (simplicia, 60<D<16 mesh powder, and D≤60 mesh powder) and herb mass, which further extracted in reflux and infusion method. Herbs with 60<D<16 mesh size and D≤60 mesh powder were extracted by infusion in 200 mL water, and leaf herbs were extracted by reflux in 600 mL water. The results show that increases in extracted herb mass related to the increasing in quercetin concentration. For future product commercialization purpose, quercetin concentration in leaves needs to be equal to its concentration within the range of particle size variation. Quercetin concentration in the leaves (459.91 ppm) was almost equal to that for 2.4 gram herbs in 60<D<16 mesh powder (489.09 ppm). The highest total flavonoid content was achieved in 2.4 gram 60<D<16 mesh herb powder with 41.508 mg QE (Quercetin Equivalent)/g. Therefore, it can be concluded that the anti-atherosclerotic herbs contain quercetin.