Su Mu, also known as Su Fang, Chi Mu, and Hong Chai, is mentioned in the book "Southern Plants and Trees". It is the dried heartwood of the leguminous plant Caesalpinia sappan L. It is mostly harvested in autumn, with the white sapwood removed and dried.
[Processing Method] According to the "Lei Gong Pao Zhi Lun": "It must be finely filed and vigorously pounded." Currently, the original medicinal material is taken, impurities are removed, and it is sawn into segments about 3cm long. It can be split into slices or ground into coarse powder, or the sawn segments can be planed into thin slices.
[Appearance of the medicinal slices] They are irregular and extremely thin slices or coarse powder, red-yellow or yellow-brown in color. The extremely thin slices or small fragments have a yellow-white marrow visible in the center, with a few pieces containing yellow-white sapwood. The texture is dense and hard. It has no odor and a slightly astringent taste.
[Processing function] Su Mu has a sweet and bitter taste, and is neutral in nature. It enters the heart, liver, and spleen meridians. It has the functions of promoting blood circulation, eliminating blood stasis, reducing swelling, and relieving pain. It is used for dysmenorrhea, postpartum blood stasis, chest and abdominal pain, and traumatic swelling and pain. This herb is mostly used in its raw form, such as in the herbal decoction of Su Fang Mu for treating women with irregular menstruation, restlessness, and pain (from "Tai Ping Sheng Hui Fang"); or in the Su Mu wine for treating injuries and ulcers caused by wind-dampness (from "Sheng Ji Zong Lu"). After processing, it can make the medicinal material clean and easy to mix and formulate into preparations.
