Houttuynia cordata Thunb. (H.cordata), which is local plant in Northern Thailand, has a wide range of biological activities including anti-cancer and anti-inflammatory activities. It consists of several components such as flavonoids, volatile oils and alkaloids. Major representatives of flavonol subgroup of flavonoids found in H.cordata are rutin, quercetin, quercitrin, isoquercitrin and hyperin. Despite the fact that flavonoids show various beneficial properties, there are few studies involving isoquercetin and rutin. In this study we aimed to investigate whether H.cordata extract, isoquercetin and rutin possess anti-leukemic effects through an apoptotic pathway in K562 human leukemic cells. Using the XTT assay we found that H.cordata extract, isoquercetin and rutin inhibited growth of K562 cells with IC50 values of 414.35 ± 5.78 μg/ml, 71.14 ± 4.49 μg/ml and 98.56 ± 6.35 μg/ml, respectively. In microscopic analysis, blebbing pattern of cell apoptosis was found in cells treated with isoquercetin (50 μg/ml) and H.cordata extract (250 and 300 μg/ml) at 48 h. Furthermore, H.cordata extract and isoquercetin induced a significant increase in K562 cells death through apoptosis at 12 and 24 h after analyzed by flow cytometry. In conclusion, our finding highlight the fact that H.cordata has anti-leukemic activity via apoptotic induction but certainly much more molecular mechanism research is needed.