Cancer metastasis represents the most important cause of cancer death and antitumor agents that may inhibit this process have been extensively pursued. Invasion and metastasis of malignantly transformed cells involve degradation of the extracellular matrix (ECM) components by matrix metalloproteinases (MMP), especially MMP-2 and -9. We previously showed that H-ras-induced invasive phenotype may involve MMP-2, rather than MMP-9, in MCF10A cells. In the present study, we investigated the chemopreventive effect of Aster, a widely used culinary vegetable in Korea. We screened twelve extracts from three Aster species (Aster scaber, Aster oharai and Aster glehni) for the inhibitory effect on MMP activities of H-ras MCF10A human breast epithelial cells. All of the extracts tested in this study efficiently inhibited the gelatinolytic activities of MMP-2 and MMP-9. A more prominent inhibition was observed in MMP-2 activity compared to MMP-9. Out of twelve extracts, eight extracts showed>90％ inhibition of MMP-2 activity in H-ras MCF10A cells while only one extract showed>90％ inhibition of MMP-9 activity. We selected three extracts (AO-3, AG-3 and AS-EA) for further studies since they exerted a marked inhibition in the ratio of MMP-2 to MMP-9. Treatment with AO-3, AG-3 and AS-EA in H-ras MCF10A cells caused a significant inhibition of invasive phenotype and migration, proving a chemopreventive potential of these extracts. Taken together, our results demonstrate that extracts of Aster effectively inhibit invasion and migration of highly malignant human breast cells, possibly via downregulation of MMP-2 and MMP-9.