Zi Su Geng

Perilla frutescens is an aromatic annual herb of the family Lamiaceae native to East and Southeast Asia and widely cultivated in China, Japan and Korea both as a culinary herb and as a source of three distinct medicinal materials — leaf (Zi Su Ye), seed (Zi Su Zi) and stem (Zi Su Geng). The plant reaches 60-150 cm in height with a quadrangular, finely pubescent stem that is green to deep purple depending on cultivar. The opposite, long-petiolate leaves are broadly ovate, 7-12 cm long, with coarsely serrate margins, green or purple, and emit a strong perfumy, somewhat cinnamon-clove scent when bruised. Small white to pinkish-purple two-lipped flowers are borne in slender terminal and axillary racemes, followed by small reticulate nutlets. The medicinal stem is the upper part of the main stem, cut into oblique slices showing a wide white pith.