It can promote absorption and has many functions. Chestnut thorns are rich in tannins, which have detoxification effect and relieve aging. Chestnut shell burr is chestnut crown, which can be used to treat chronic bronchitis, cough with excessive phlegm, whooping cough, lymphadenitis, mumps and other diseases; Chestnut shell contains phenols, organic acids, sugars, polysaccharides (or glycosides), lactones, coumarins, tannins, steroids (or triterpenoids) and flavonoids.

Extended data:

The shell of this plant, chestnut. The original plant Castanea mollissima is a deciduous tree with a height of1.5 ~ 20m. The bark splits deeply longitudinally; The shoots are hairy; Winter buds are short, broadly ovoid and hairy. Leaves in 2 rows, oval to elliptic lanceolate, 9 ~15cm long, rounded or broadly cuneate at the base, sometimes inclined, pinnately veined, serrated at the edge, awned at the tooth tip, glabrous at the top or sparsely stellate pubescence of young leaves, densely covered with white stellate villi and long single hairs at the bottom; Petiole is short. Flowers bloom in summer.

References:

Baidu encyclopedia-chestnut shell