Yam, also known as Dioscorea in ancient times, is the tuberous root of the perennial plant Dioscorea opposita from the Dioscoreaceae family. The variety produced in Henan (ancient Huaiqing Prefecture) is considered superior, hence it is also called Huai yam. It is one of the four major Huai herbs (namely Huai yam, Huai rehmannia, Huai achyranthes, and Huai chrysanthemum). It is often used raw or stir-fried.
I. Efficacy and Application
Chinese yam tastes sweet and has a neutral nature. It belongs to the spleen, lung, and kidney meridians.
Efficacy It can replenish qi and nourish yin, tonify the spleen, lungs, and kidneys. Its characteristic is that it serves both as medicine and food, rich in nutrients, smooth and tender, juicy, making it a key herb for nourishing true yin. Since ancient times, it has been praised as the "jade of the mountains" and "food of the immortals."
Commonly used for the treatment of conditions such as spleen deficiency with reduced appetite, chronic diarrhea, lung deficiency with cough and asthma, kidney deficiency with seminal emission, leukorrhea, frequent urination, and deficiency heat with wasting thirst.
Summary of Masterpieces by Renowned Authors
The Classic of Materia Medica: "It primarily treats internal injuries, supplements deficiency and emaciation, eliminates cold and heat evil qi, supplements the center, boosts qi and strength, promotes muscle growth, and strengthens yin."
Bie Lu: "Treats consumptive disease with emaciation, replenishes the five viscera, eliminates vexing heat, and strengthens yin."
Rihuazi's Materia Medica: "It assists the five viscera, strengthens the sinews and bones, enhances willpower and calms the spirit, primarily treating seminal emission and forgetfulness."
Compendium of Materia Medica: "Benefits kidney qi, strengthens spleen and stomach, stops diarrhea and dysentery, resolves phlegm and saliva, moistens skin and hair."
"Treatise on Medicinal Properties": "It tonifies the five strains and seven injuries, dispels cold wind, stops lumbar pain, calms the heart spirit, supplements insufficient heart qi. For patients with physical weakness and emaciation, it can be added and used."
Shanghan Yunyao: "Tonify deficiency, clear deficiency heat."
Bencao Zheng: "Shanyao can strengthen the spleen and tonify deficiency, nourish essence and consolidate the kidneys, treat various deficiencies and damages, and heal the five strains and seven injuries... Therefore, to tonify the spleen and lungs, one must primarily use ginseng and atractylodes; to tonify kidney water, one must primarily use cornus and rehmannia; to astringe leukorrhea and turbidity, one must combine it with psoralea; to consolidate seminal emission, one must rely on cuscuta for assistance."
Changsha Materia Medica: Nourishing the earth of Wu to promote descending and restraining, supplementing the metal of Xin to govern convergence, effectively calming wind and dryness, specifically stopping dispersion.
Ben Cao Bei Yao: Enters the spleen and lung meridians, replenishes their deficiencies, clears their deficient heat. Strengthens the stomach and intestines, moistens the skin and hair, transforms phlegm and saliva, stops diarrhea and dysentery.
"Medical Records of Integrating Chinese and Western Medicine": "Yam, with its white color, enters the lung; its sweet taste returns to the spleen; its thick liquid benefits the kidneys. It can moisten the blood vessels, consolidate and regulate qi, calm cough and relieve asthma, strengthen the will and nourish the spirit. Its neutral nature allows for long-term and frequent consumption."
II. Compatibility and Application
1. For spleen deficiency and qi weakness, reduced appetite, loose stools or diarrhea, etc. Chinese yam not only tonifies the spleen and boosts qi but also has astringent properties, making it particularly suitable for those with spleen deficiency and diarrhea. To treat the above conditions, it is often combined with ginseng, white atractylodes, poria, and white hyacinth bean, forming the renowned formula for tonifying the spleen and boosting qi, known as Shenling Baizhu San.
Throughout history, no one has been more adept at using Chinese yam than Zhang Xichun. Zhang himself formulated many renowned prescriptions to treat conditions such as deficiency-induced asthma, consumptive diseases, and even critical illnesses. He often administered large doses gradually, achieving remarkable results repeatedly. For instance, there was a woman who suffered from persistent diarrhea for several months, with her condition becoming critical and all other treatments proving ineffective. Zhang Xichun used only raw Chinese yam, finely ground, instructing her to cook it into porridge and consume it three times a day. Within two days, she recovered completely, and after a few more days of consumption, her health was fully restored. The efficacy of Chinese yam in tonifying the spleen, stopping diarrhea, and stabilizing collapse was demonstrated to the fullest extent.
2. For lung deficiency with cough and dyspnea, consumptive disease, etc. Chinese yam is good at tonifying lung qi and benefiting lung yin, thus it is effective in treating chronic cough or dyspnea due to lung deficiency. For example, Ginseng, Poria and Atractylodes Macrocephala Powder can not only stop diarrhea but also has the effect of "strengthening earth to generate metal", tonifying spleen and replenishing qi, making it an excellent formula.
If treating yin deficiency and fluid depletion, it is often combined with Codonopsis pilosula, Ophiopogon japonicus, Schisandra chinensis, and other yin-nourishing herbs.
Zhang Xichun treated consumptive diseases such as cough and asthma by formulating multiple prescriptions, all of which heavily utilized Chinese yam, setting an exemplary model for others. For instance, to address conditions like consumptive emaciation, poor appetite, cough with asthma, fever, and a weak, rapid pulse, he often combined it with Scrophulariae Radix, Atractylodis Macrocephalae Rhizoma, Galli Gigerii Endothelium Corneum, and stir-fried Arctii Fructus, creating the Zisheng Decoction. This formula can also be used to treat women with blood deficiency leading to amenorrhea.
If treating consumptive disease, squamous and dry skin with wiry, rapid, fine and minute pulse, it is often combined with Codonopsis Radix, Astragali Radix, Anemarrhenae Rhizoma, etc., which is Shi Quan Yu Zhen Tang.
If treating consumptive fever, cough with panting, and weak rapid pulse, it is often combined with Shengdi, Renshen, Xuanshen, and Maidong, known as Liquan Yin.
In cases of yin deficiency, lung deficiency with laborious breathing, or accompanied by tuberculosis, it is often combined with ginseng, ophiopogon, pinellia, and perilla fruit, known as Ginseng and Ophiopogon Decoction.
In the treatment of patterns characterized by upper heat and lower cold, as well as dual deficiency of yin and yang, it is often combined with prepared rehmannia root, cornus fruit, aconite, and dragon bone, which is known as the Ji Ji Decoction.
In addition, in formulas such as Pearl and Jade Two Treasures Porridge, Rich Snow Decoction, Tranquilizing and Calming Decoction, Ginseng and Ochre Tranquilizing Qi Decoction, Yam Qi-Containing Decoction, Nourishing and Cultivating Decoction, and Warming the Thoroughfare Vessel Decoction, yam is used in large quantities.
If treating consumptive fever, or wheezing cough, or spontaneous sweating, or palpitations, or inhibited urination, diarrhea, and all signs of yin depletion, Zhang Xichun took the use of Chinese yam to the extreme, simply using this single herb in large doses taken slowly to secure the true qi, known as the Single Herb Chinese Yam Decoction.
Zhang Xichun said, "The nature of Chinese yam is such that it can nourish yin and also promote diuresis, it can lubricate and also astringe. Therefore, it can tonify the lungs, tonify the kidneys, and also tonify the spleen and stomach. Moreover, it contains the most protein, making it truly the supreme product among tonic herbs. Its properties are very mild and harmonious, making it suitable for frequent and prolonged consumption."
Huang Yuanyu said, "The nature of Chinese yam is good at entering the lungs and stomach to gather the essence and spirit. When supplemented with products that regulate and nourish the spleen and liver, it is truly a good medicine for all kinds of deficiency and fatigue diseases."
3. For kidney deficiency, nocturnal emission, frequent urination, excessive leucorrhea in women, and other syndromes. Chinese yam can tonify the kidney and also has an astringent effect. To treat nocturnal emission due to kidney deficiency, it is often combined with prepared rehmannia root, cornus fruit, and moutan bark, as in the Liuwei Dihuang Pill.
In treating kidney deficiency with insecurity and inhibited urination, Zhongjing often combines prepared rehmannia root, moutan bark, aconite, and cinnamon, which is known as the Kidney Qi Pill.
For treating frequent urination due to kidney deficiency, it is often combined with Alpiniae Oxyphyllae Fructus and Linderae Radix, known as Suoquan Pill.
If treating excessive leukorrhea in women, it is often combined with spleen-invigorating and dampness-eliminating herbs such as ginseng, atractylodes, white atractylodes, and plantain seeds, which is known as the Wan Dai Tang.
If treating yellow leukorrhea with damp-heat, it is often combined with Phellodendron chinense, Euryale ferox, and Ginkgo biloba, known as Yi Huang Tang.
Zhang Xichun often used raw Chinese yam in combination with raw dragon bone, raw oyster shell, cuttlebone, and madder to treat women's red and white vaginal discharge, which is known as Qing Dai Tang. For treating white discharge, add deer antler glue and white atractylodes; for treating red discharge, add white peony root and flavescent sophora root.
4. Used for treating diabetes. Chinese yam tonifies qi and nourishes yin, making it particularly suitable for treating diabetes. For example, Zhang Zhongjing's Shenqi Wan, Qian Yi's Liuwei Wan, and modern Xiaoke Wan are all commonly used formulas.
Large doses of Chinese yam can be used as a tea substitute, which can also nourish yin and treat diabetes, known as the Single Ingredient Chinese Yam Drink.
If combined with Astragalus, Pueraria, Anemarrhena, and Trichosanthes root, it becomes Jade Fluid Decoction. If combined with Astragalus, Rehmannia, and Cornus officinalis, it becomes Nourishing Pancreas Decoction.
The above two prescriptions are famous formulas by Zhang Xichun for treating diabetes, which can be used in combination. The author composed a mnemonic verse as follows:
Yuye Ziyi Decoction is formed by combining two prescriptions into one.
Five Astragali, Mountain Pig, Kudzu, Rehmannia, Cornus Powder, Gold
Adjust according to symptoms, Xiaoke Jiangtang Ling.
5. For the difficult condition of warm disease with dryness-heat accompanied by slippery diarrhea. Chinese yam can nourish yin and moisten dryness, and is also good at stopping diarrhea and securing retention. For warm disease with upper burner dryness-heat, accompanied by slippery diarrhea, or panting, cough, and weak rapid pulse, it is often combined with talc, licorice, and raw white peony root, as in the Nourish Yin and Clear Dryness Decoction.
Zhang Xichun said, "In cases of cold and warm syndromes, dryness and heat in the upper burner and slippery diarrhea in the lower burner are both dangerous signs. If one intends to treat dryness and heat with cooling and moistening methods, it may hinder the treatment of slippery diarrhea; if one intends to treat slippery diarrhea with astringent and tonifying methods, it may hinder the treatment of dryness and heat. When I encounter such syndromes, I often use raw Chinese yam, supplemented with talc. Generally, slippery diarrhea stops after one dose, and dryness and heat are greatly alleviated. If residual heat remains and is not completely eliminated, it is acceptable to gradually adjust with cooling and moistening herbs."
In addition, Yue Meizhong treated uterine fibroids by combining raw leeches with raw Chinese yam, grinding them together into powder for oral administration, which can be considered a unique innovation. In the formula, Chinese yam not only has the effect of supporting the body's vital energy and moderating the leeches but also serves as an excipient.
III. Usage and Dosage
Yam is often used in decoctions and also commonly made into pills or powders. It is both a medicine and a food, safe and reliable, so it can be used with confidence. The general dosage ranges from over ten grams to several tens of grams; if it is the main ingredient in a prescription for emergency treatment to stabilize collapse, it can also be used in amounts exceeding one hundred grams.
Yam is a substance that serves both medicinal and dietary purposes. Its medicinal properties are neither cold nor dry, with a sweet taste and moist texture, and its effects are gentle. It can both tonify qi and nourish yin, tonifying without causing stagnation, moistening without being greasy. Rich in nutrients and easily digestible and absorbable, it has long been regarded as an excellent supplement for deficiency. It can be used as a staple food or as a vegetable, being sweet, delicious, soft, and sticky. It is particularly suitable for those with prolonged illness and physical weakness, weak spleen and stomach, poor appetite, and intolerance to aggressive treatments, and can be taken long-term.
The author believes that in ancient times, yam had so many effects because it contains a large amount of protein, amino acids, starch, sugars, vitamins, and other essential nutrients for the human body. At the same time, it is smooth, tender, and juicy, greatly nourishing true yin, making it suitable for those with prolonged illness and weak constitution, or for impoverished people. It is also a rare, high-quality, and affordable product. Zhang Xichun precisely uncovered the functions of yam in "greatly nourishing protein" and "greatly nourishing true yin," which allowed it to perform miraculously in many critical medical cases, truly setting an example for great physicians.
Yam should be used raw to tonify deficiency and nourish yin, and stir-fried to strengthen the spleen and stop diarrhea.
Zhang Xichun said, "It is advisable to use the raw form by boiling it to extract the juice for consumption; it should not be stir-fried, as it contains a high amount of protein. Stir-frying will cause the protein to become charred and ineffective when ingested. If making pills or powders, it can be finely ground and steamed before use."
IV. Application Notes
Yam nourishes yin but promotes dampness, so it is contraindicated for those with excessive dampness and fullness in the middle jiao or those with stagnation.
In addition, after decocting Chinese yam, the medicinal liquid is prone to sedimentation, so it can be shaken before taking.
Practical Notes on Traditional Chinese Medicine: Second Draft, January 23, 2021#TCM Practical Notes#
