✵The TCM herbalism is also known as pharmaceutics of Traditional Chinese Medicine, or Chinese pharmaceutics, is the branch of health science dealing with the preparation, dispensing, and proper utilization of Chinese herbs. It is majorly composed of Introduction of Chinese Medicinals, Classification of Chinese Herbs, Formulas, and Patent medicines.
Classifications of Herbs:Herbs for External Use.
Introduction: Herbs for External Use: an agent or substance herbs that used externally for external disease.
✵Till the date March 19th, 2020, there are totally  kinds of common TCM herbs,  kinds of related plant species,  kinds of related insect species,  kind of minerals, are recorded in this category. These herbs for external Use are briefly introduced separately:
Semen Crotonis(Croton Seed).
Brief Introduction: The herb Semen Crotonis is the dried ripe seed of Croton tiglium L(family Euphorbiaceae), used externally for treating scabies, tinea, and warts. The herb is commonly known as Semen Crotonis, Croton Seed, Croton tiglium, Fructus crotonis, Purging croton, Bā Dòu.
✵Common official herbal classics and other famous herbal classics defined the herb Semen Crotonis(Croton Seed) as the dried ripe seed of the species Croton tiglium L. It is a plant species of the Croton L. genus, the Euphorbiaceae family of the Euphorbiales order. This commonly used species is introduced as:
Croton tiglium L.: It is commonly known as Bā Dòu. Shrubs or small trees, 3~6 meters high; Shoots sparsely stellate pilose, branches glabrous. Leaves papery, ovate, sparse, elliptic, 7~12 cm long, 3~7 cm wide, apically shortly, sparse acuminate, sometimes long acuminate, base broadly cuneate to suborbicular, sparse cordate, margin serrate, sometimes subentire, growing leaves glabrous or subglabrous, yellowish to pale brown after dry; 3~5 basal veins, 3~4 pairs of lateral veins; There are 1 disk glands on leaf margin on both sides of base; Petioles 2.5-5 cm long, subglabrous; Stipules linear, 2~4 mm long, early falling.
Racemes, terminal, 8~20 cm long, bracts subulate, ca. 2 mm long; Male flowers: buds subglobose, sparsely stellate hairs or almost glabrous; Female flowers: sepals oblong-lanceolate, ca. 2.5 mm, rarely glabrous; Ovary densely stellate pilose, style 2-lobed.
Capsule ellipsoid, ca. 2 cm long, 1.4~2 cm in diameter, sparsely stellate or subglabrous; Seeds elliptic, ca. 1 cm long, 6~7 mm in diameter, it is flowering from April to June.
Ecological environment: the plant grows near the village or mountain forest, or only see cultivation. It prefers a warm and humid climate, not cold, afraid of frost. Like sunshine, suitable for cultivation in areas with temperature 17~19 ℃, annual rainfall of 1,000 mm, annual sunshine of 1,000 hours and a frost-free period of 300 days or above. When the temperature is lower than 3 ℃, all seedlings and leaves die. It is advisable to cultivate on sandy soil with sufficient sunshine, deep soil, loose and fertile soil, and good drainage. It is produced in the Zhujiang river area, southwest, the middle and lower reaches area of the Yangtze River, and other areas of China.
Trait identification: The herb is ovoid with 3 edges, 1.8~2.2 cm long and 1.4~2 cm in diameter. Surface grayish-yellow or slightly deep, rough, with 6 vertical lines, apex truncate, base fruited. When the shell is opened, there are 3 cells, each containing 1 seed. Seeds elliptic, slightly flattened, 1.2~1.5 cm long, 7~9 mm in diameter; The surface is brown or grayish brown, one end has the seed hilum and the seed mound scar, the other end has the indentation, between has the raised seed ridge; The outer coat was thin and brittle, and the inner coat was white film. Kernel yellow-white, oily. No smell, spicy taste. The herb which is big, full, yellow and white kernel color is better.