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It is Polygonatum odoratum (Polygonati Odorati Rhizoma), also known as Dijie.

[Clarification of Doubts] In the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), Weirui and Nüwei are listed under the same entry. Later, a separate entry for "Nüwei" marked with a circle was added. Li Shizhen (Binhu) stated that the "Nüwei" in the *Bencao Jing* corresponds to "Weiwei" in the *Erya* (which is the Weirui recorded in the *Xinxiu Bencao Jing*). This was an error in ancient copying, where "Weiwei" was mistakenly written as "Nüwei". The "Nüwei" listed separately later with a circle mark is indeed distinct from Weirui; it is a creeping herb. Weirui has long, narrow leaves and stems resembling those of Polygonatum sibiricum (Huangjing), stiff and straight like bamboo with nodes. Its root is yellow, grows horizontally like the roots of Miscanthus (Digeng) or Acorus tatarinowii (Changpu). Generally, the nodes are flat and straight and rich in mucilage; even when dry, it remains soft. The rhizomes have dense, redundant joints, resembling hanging tassels, presenting an appearance of dignity and majesty. Hence, the *Xinxiu Bencao Jing* named it "Weirui". Nüwei resembles Ampelopsis japonica (Bailian) but grows as a vine; its shoots are used rather than its roots. It tastes pungent and is warm in nature, treating cholera and dysentery, which is completely different from the sweet and neutral nature of Weirui. Additionally, Ruiren used for treating eye diseases is a different substance and not the seed of Weirui.

The root has a sweet flavor and neutral temperature. It acts on the Stomach and Spleen, possessing ascending and descending properties, belonging to Yin within Yang. The *Bencao Jing* states it treats sudden heat due to wind-stroke, inability to move, tendon contractions with flesh nodules, and various deficiencies. Long-term use improves complexion, adds luster, lightens the body, and delays aging. Various materia medica texts state it tonifies the Middle and boosts Qi, regulates Blood and Qi, benefits Essence, treats Stomach deficiency and fatigue, addresses wind invading the four extremities, moistens skin, removes dark spots, relieves irritability, stops thirst, moistens the Lungs and Heart, treats chest/abdominal stagnation and deficient heat, cures damp-toxin lower back pain, warms the waist and knees, dispels wind-warmth and epidemic fevers, and treats cold-heat bi-syndrome caused by chronic malaria. It should not be taken by those with excess heat.

[Discussion] Regarding the flavors of the Five Directions: The Stomach belongs to Wu Earth; its primary Qi is neutral, with secondary attributes of warm, cool, cold, and hot. The Spleen belongs to Ji Earth; its primary taste is salty, with secondary tastes of pungent, sweet, sour, and bitter. This differs from the theory that "Central Earth generates Sweet, thus its taste is sweet." Generally, in the Five Elements, what overcomes oneself is the master, and what one overcomes is the function. The reason the Spleen's primary taste is said to be salty is from the perspective of its functional application. Weirui has a neutral Qi and sweet taste, truly being the correct agent for Central Earth. Its function is to tonify the Middle and boost Qi. However, the *Bencao Jing* lists treating wind-stroke sudden heat as the primary indication because the function of Central Earth in transformation and generation relies entirely on Wind-Wood acting as a unique envoy. From the place of transformation and generation, it divinely regulates ascending and descending to complete the cycle of Yin and Yang, thereby allowing Ying and Wei (Defensive and Nutritive Qi) to flow freely. Thus, the taste of Wood is also sweet, illustrating the principle that "what one overcomes serves as the function." Since this substance embodies Earth but serves the function of Wood, and Wood utilizes the Qi-transformation of Earth, why is treating wind considered its primary merit? If Wood and Earth in the human body do not harm each other, vital energy is complete; if they do not support each other, physiological life ceases. This drug divinely regulates ascending and descending within Central Earth; therefore, all conditions it treats are clear evidence of the mutual use of Wood and Earth (such as tendon contractions with flesh nodules). Broadly speaking, when Liver and Spleen harmonize, Qi and Blood are generated. For diseases arising from disharmony between Liver and Spleen, this herb seems to be a crucial medicine. One might ask: As a single Yin envoy, it certainly reaches Yang through wind-assisted ascent. But the Lung is what enables Yin descent so Yang follows. Why is it associated with the Liver? The answer is: Metal uses what it overcomes as its function, and its taste is sour. This means Metal must combine with Wood to achieve descent. Is it not true that it divinely regulates ascending and descending within Central Earth? Yang governs ascent; after Yang ascends, Yin follows upward. Yin governs descent; after Yin descends, Yang follows downward. Yin and Yang are the pre-heaven basis of Ying and Wei, while Ying and Wei are the post-heaven manifestation of Yin and Yang. Therefore, the use of Wood and Earth lies only in the harmony of ascending and descending to exhaust their variations. This herb reaches Yang from within Yin, causing Yin to follow to the extreme upper, thus relieving irritability, stopping thirst, and moistening the Lungs and Heart. It reaches Yin from within Yang, causing Yang to follow to the extreme lower, thus treating damp-toxin, lower back pain, deficiency damage, waist and leg pain, foot weakness, spasmodic bi-syndrome, and rebellious Qi. It is used in Da Biejia Tang. Regarding primary diseases of the Spleen and Stomach, there is the Mai Dong Tang for Louqi Syndrome (characterized by heat in the back, pulling pain in elbows and arms, discontinuous breath, oppression in the diaphragm, vomiting followed by diarrhea after eating; this is due to wind-heat closing the cou-li [pores], meridian Qi losing its path, and evil qi settling internally). There is also Renshen Tang for Zoubu Syndrome (characterized by excess heat in the Lower Jiao, internal Qi knotting, failure to excrete dregs, turbid qi steaming into the Stomach, leading to obstruction of urination and defecation, rebellious Qi, and uncontrollable vomiting). Both utilize this herb. Regarding secondary diseases of the Spleen and Stomach, Shi Nan San for treating Re Bi-Syndrome (characterized by extreme muscle heat, sensation of mice crawling on the body, ruined lips and mouth, changed skin color) also uses it. For primary diseases of the Liver, Jinpo San for treating Fengjing (characterized by trembling limbs, confusion, and disordered spirit) uses it. For secondary diseases of the Liver (diseases of its child organ), Xijiao Wan for treating Xin Zang Zhongfeng (Wind-stroke of the Heart) employs these two formulas. Furthermore, for simultaneous disorders of Ying and Wei manifesting as epidemic fevers or cold-heat bi-syndrome from chronic malaria, it is invariably used. All these treatments demonstrate the mutual interaction of Wood and Earth. Those who are superficial and fail to investigate may rashly label it as a divine medicine suitable for everything by a virtuous gentleman, providing only material for ridicule.

[Processing] Harvest the roots, scrape off the nodal skin with a bamboo slice, wash clean, soak in honey-water overnight, steam, and then dry by baking.