Collected Illustrations of the Three Realms, Volume on Herbs and Trees, Chapter 5

Lanru

original: 蘭茹 (Lanru); historically identified as a species of Figwort (Scrophularia) or potentially a variety of Euphorbia, though the description of the sap suggests a specific medicinal variety used for topical treatments.

Lanru grows in the mountain valleys of Dai Prefecture. Today, it can also be found in Heyang, Zi, and Qi Prefectures. In the second lunar month, the sprouts emerge. The leaves resemble the Daji (Peking Spurge)|Euphorbia pekinensis, a potent and somewhat toxic herb used in traditional medicine, but the flowers are yellow. The root is shaped like a radish; its skin is a reddish-yellow, while the flesh inside is white. When the root is first cut, the sap flows out and congeals, becoming as black as lacquer.

In the third month, it blooms with light red flowers, which may also appear pale yellow; notably, this plant does not bear seeds. Tao Yinju|Tao Hongjing (456–536 CE), a renowned physician and polymath who organized the first systematic pharmacopoeia in China stated that the specimens originating from Goryeo|An ancient kingdom on the Korean Peninsula are very similar to this variety.

The roots should be harvested in the fourth and fifth months and dried in the shade. Those that possess the "lacquer head" The dark, resinous cap formed by the dried sap at the cut end of the root are considered to be of the highest quality. There is another variety known as "Grass Lanru" which is white in color. Unscrupulous harvesters sometimes use a red-hot iron to sear the tips of these white roots to turn them black, attempting to pass them off as the genuine "lacquer head" variety; these are not the true medicine.

This herb is also known by the names Quju or Liwei.

Properties and Usage:
Its flavor is pungent and sour; its nature is slightly cold and contains a small amount of toxin. It is primarily used to erode necrotic flesh, treat festering sores, and remove dead muscle tissue. It is effective at killing scabies mites, draining pus, and eliminating "bad blood" Refers to stagnant or infected blood according to traditional pathology.

Furthermore, it expels "Great Wind" A historical term for severe skin diseases or neurological conditions like leprosy and heat energy. It is used to treat forgetfulness and melancholy. It also relieves "heat obstruction" Pain or numbness caused by heat and dampness, breaks down Zhengjia|Hard abdominal masses or tumors believed to be caused by stagnant energy and blood, and removes polyps.