The difference between the red and green stems of Swertia japonica Thunb lies in the growth time of the vegetable. The stems of Swertia japonica Thunb are green at the early mature stage. With the increase of growth time, the stems of Swertia japonica Thunb gradually darken in color and finally reach the red stems. Swertia japonica Thunb., densely clustered, oval to round, obovate or oval in shape, with many thin branches, pubescence and semi-lignified stem base. There are many branches in the stem, the leaves are linear and lanceolate, and the leaves are simple and alternate, and the leaves are linear, linear or strip.