The Korean folk medicine "Da-Rae-Jul-Ki" is used to treat various diseases including dysuria, stroke, intestinal catarrh, and stomach cancer. This crude drug is considered to originate from the branches of Actinidia species, but this has not been pharmacognostically confirmed. To clarify the botanical origin of "Da-Rae-Jul-Ki," we conducted a comparative anatomical study using branches of Actinidia species growing wild in South Korea and Japan. These included A. arguta, A. arguta var. rufinervis, A. kolomikta, A. polygama, and A. rufa. Our study revealed morphological criteria that distinguished each of these four species and one variety of Actinidia from the others. These criteria included the number of cell layers in the cork; the size of cork cells; the ratio of the width of the secondary cortex to that of the primary cortex; the presence of stone cells between fiber bundles; and the sizes of stone cells, vessels, and parenchyma cells in the pith. Using these criteria, we determined that "Da-Rae-Jul-Ki" is derived from the branches of A. arguta.