Shan Yao - 山药 - Rhizoma Dioscoreae

Properties: Sweet, neutral

Meridans Entered:
Primary: Spleen, Lung and Kidney
Extraordinary Vessels: Chong, Dai

Traditional Actions/Indications:

Tonifies the Spleen, nourishes Stomach Yin and stops diarrhoea
Spleen or Stomach Deficiency with diarrhoea, fatigue, spontaneous sweating and anorexia
Tonifies Lung Qi and nourishes Lung Yin
Lung Qi and/or Yin Deficiency with chronic cough
Tonifies Kidney Yin and astringes Jing
Kidney Qi Deficiency with spermatorrhea, urinary frequency and vaginal discharge
消渴 Xiao Ke due to Qi and Yin Deficiency
Aids fasting
Mentioned in the Shen Nong Ben Cao Jing as part of the superior class of herbs which can, with protracted taking, sharpen the ears and eyes, make the body light, make one free from hunger and prolong life. This may suggest it was part of supplementing the diet when engaging in an "avoiding grain" (Bigu 辟穀) fasting regime to cultivate life (Yangsheng 養生). Despite being a starchy vegetable, this may still have been an appropriate addition to a ketogenic diet as the starches are mostly resistant and many of its other compounds have been shown to have blood glucose reducing effects, making it a potential important source of this essential nutrient group while engaging in a low carbohydrate diet.

Suggested Daily Dosage: 5-30g in decoction. Very large doses, up to 500g have been used in trials for diabetes management.

Notable Constituents:

Starch
Long polysaccharide chains which constitute ~65% of the content of Chinese yam (Epping & Laibach, 2020). However, around half of these are resistant starches (Khol et al., 2024), a proportion which may rise with cooking (Alharazi et al., 2021), enabling them to feed the gut microbiome without spiking blood glucose levels.
Dioscin
Steroidal saponin spirostanyl glycoside of diosgenin with antifungal, antiviral, antineoplastic, anti-inflammatory, hepatoprotective, apoptosis inducing and tyrosinase inhibitory actions. It has also shown antidiabetic effects through lowering blood glucose levels, inhibiting lipid deposition, protecting pancreatic Β-cells, and inhibiting abnormal oxidative stress and inflammatory responses (Gao et al., 2024).
Diosgenin
Precursor to several hormones including progesterone.
Allantoin
A product of the oxidation of uric acid and present in the urine of most mammals except higher primates. It has healing, soothing, and anti-irritating properties; helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. It is often found in anti-acne products, sun care products, and clarifying lotions as well as toothpaste, mouthwash, and other oral hygiene products, shampoos, lipsticks, cosmetic lotions and creams, and other cosmetic and pharmaceutical products where it is usually extracted from cow urine or the comfrey plant. It has been shown to enhance insulin secretion from Β-pancreatic cells through imidazoline I-3 receptor activation (Tsai et al., 2014; Amitani et al., 2015)
Batatasin I
A phenanthrene derivative, it has shown anti-inflammatory effects by inhibiting eicosanoid generation and degranulation in mast cells.
Batatasin III
A stilbenoid, it has been found to inhibit cancer cell migration and invasion by suppressing epithelial-to-mesenchymal transition (EMT) and related signaling pathways like FAK and AKT. It also demonstrates anti-inflammatory effects.
Batatasin IV
A stilbenoid and Leukotriene A4 Hydrolase inhibitor, that also exhibits anti-inflammatory activity.
Dopamine
Catecholamine neurotransmitter that is important in the extrapyramidal system of the brain which regulates movement, and also responsible for motivation, reward, mood and attention. Its dysregulation can result in disorders such as Parkinson's, schizophrenia, depression and addiction.

Notes:

Generally considered identical to Dioscorea villosa used in western herbal medicine as a Yin tonic for its diogenin content.

Appears in 60 formulae listed on this site: (click to display)

An Tai Zhu Gao (Foetus Quieting Plaster)
From: Rhymed Prose on Medical Principles and Applications (1870)

Ba Wei Di Huang Wan (Eight Ingredient Pill with Rehmannia)
From: Fu Qing-Zhu's Women's Disorders by Fu Qing-Zhu (1826)

Ba Xian Chang Shou Wan (Mai Wei Di Huang Wan) (Eight Immortal Pill for Longevity)
From: Achieving Longevity by Guarding the Source by Gong Ting-Xian (1615)

Bao Tai Zi Sheng Wan (Protect the Foetus and Aid Life Pill)
From: Extensive Notes on Medicine from the First Awakened Studio (1613)

Bu Gu Wan (Tonify the Bone Pill)
From: Guang An Men Hospital (1990) by Guang An Men Hospital

Bu Shen Gu Chi Wan (Tonify the Kidneys to Firm the Teeth Pills)
From: Chengdu Jiuzhitang Jinding Pharmaceutical Co., Ltd.

Bu Shen Zhi Chan Tang (Tonify the Kidneys to Stop Tremors Decoction)
From: Encephalopathy Department, Shanghai Municipal Hospital of Traditional Chinese Medicine by Wentao Li

Chang Ning Tang (Intestinal Serenity Decoction)
From: Fu Qing-Zhu's Women's Disorders by Fu Qing-Zhu (1826)

Da Bu Yuan Jian (Great Tonify the Primal Decoction)
From: Collected Treatises of Jing-Yue by Zhang Jie Bin / Zhang Jing Yue (1624)

Dan Shen Shi Hu Jiu (Salvia and Dendrobium Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Di Huang Shen Jin Jiu (Rehmannia and Lycopodium Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Du Qi Wan (Capital Qi Pill)
From: Symptom, Cause, Pulse and Treatment (1706)

Er Dong Er Di Jiu (Two Winters Two Earths Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Er Long Zuo Ci Wan (Pill for Deafness that is Kind to the Left (Kidney))
From: Discussion of Warm Epidemics (1642) by Wu You-Xing / You-Ke

Er Shan Jiu (Two Mountains Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Fu Tu Dan (Poria and Cuscuta Special Pill)
From: Formulary of the Pharmacy Service for Benefiting the People of the Taiping Era by Tai Yi Ju (Imperial Medical Bureau) (1107)

Gu Chi Wan (Firm the Teeth Pills)
From: Combined gu chi wan and spiramycin in the treatment of periodontal disease by Zhang JZ, Yang XX & Tong YH (1992)

Gu Yin Jian (Stabilise the Yin Decoction)
From: Collected Treatises of Jing-Yue by Zhang Jie Bin / Zhang Jing Yue (1624)

Gu Zhen Tang (Stabilise the True Decoction)
From: Indispensable Tools for Pattern Treatment by Wang Ken-Tang (1602)

Gua Lou Qu Mai Wan (Trichosanthes and Dianthus Pill)
From: Essentials from the Golden Cabinet by Zhang Zhong-Jing (c. 220)

Huan Shao Dan (Rejuvenation Special Pill)
From: Hong's Collection of Experimental Formulas (1170)

Huang Qi Shi Hu Jiu (Astragalus and Dendrobium Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Ji Sheng Shen Qi Wan (Life Saver Kidney Qi Pill)
From: Formulas to Aid the Living by Yan Yong-He (1253)

Jia Wei Liu Wei Di Huang Wan (Augmented Six Ingredient Rehmannia Pill)
From: Golden Mirror of the Medical Tradition by Wu Qian (1742)

Jia Wei Mai Men Dong Tang (Modified Ophiopogonis Decoction)
From: Essays on Medicine Esteeming the Chinese and Respecting the Western by Zang Xi Chun / Zang Shou Fu (1918-1934)

Jian Ling Tang (Construct Roof Tiles Decoction)
From: Essays on Medicine Esteeming the Chinese and Respecting the Western by Zang Xi Chun / Zang Shou Fu (1918-1934)

Jian Pi Wan (Strengthen the Spleen Pill)
From: Indispensable Tools for Pattern Treatment by Wang Ken-Tang (1602)

Jin Gui Shen Qi Wan / Cui Shi Ba Wei Wan (Kidney Qi Pill from the Golden Cabinet / Cui's Eight Ingredient Pill)
From: Essentials from the Golden Cabinet by Zhang Zhong-Jing (c. 220)

Liu Wei Di Huang Wan (Six Ingredient Rehmannia Pill)
From: Craft of Medicines and Patterns for Children by Qian Yi (1119)

Miao Xiang San (Marvellously Fragrant Powder)
From: Formulary of the Pharmacy Service for Benefiting the People of the Taiping Era by Tai Yi Ju (Imperial Medical Bureau) (1107)

Ming Mu Di Huang Wan (Improve Vision with Rehmannia Pill)
From: Scrutiny of the Precious Jade Case (1642) by Fu Ren-Yu

Qi Ju Di Huang Wan (Goji Berry, Chysanthemum and Rehmannia Pill)
From: Craft of Medicines and Patterns for Children by Qian Yi (1119)

Qi Pi Wan (Open the Spleen Pill)
From: Restoration of Health from the Myriad Diseases by Gong Ting-Xian (1587)

Qian Lie Shu Wan (Prostate Comfort Pills)
From: Aura Herbs (2020)

Qing Dai Tang (Clear Discharge Decoction)
From: Essays on Medicine Esteeming the Chinese and Respecting the Western by Zang Xi Chun / Zang Shou Fu (1918-1934)

Qing Fei Pai Du Tang (Lung Clearing and Detoxifying Decotion)
From: Traditional Chinese Medicine: an effective treatment for 2019 novel coronavirus pneumonia (NCP) by Du et al. (2020)

Ren Shen Wu Mei Tang (Ginseng and Mume Decoction)
From: Systematic Differentiation of Warm Pathogen Diseases by Wu Tang / Wu Ju Tong (1798)

Shan Yao Jiu (Dioscorea Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Shan Zhu Cong Rong Jiu (Dioscorea, Cornus and Cistanches Wine)
From: Chinese Medicinal Wines and Elixirs (2008) by Various

Shen Ling Bai Zhu San (Ginseng, Poria and Atractylodes Powder)
From: Medical Formulas Collected and Analysed by Wang Ang (1682)

Shen Ling Bai Zhu San (Ginseng, Poria and Atractylodes Powder)
From: Formulary of the Pharmacy Service for Benefiting the People of the Taiping Era by Tai Yi Ju (Imperial Medical Bureau) (1107)

Shen Qi Di Huang Tang (Codonopsis, Astragalus and Rehmannia Decoction)
From: Illuminating the Origins of Miscellaneous Diseases with a Rhinoceros Candle: Colorectal Disease by Shen Jinao (1773)

Shi Bu Wan (Ten Tonic Pill)
From: Formulas to Aid the Living by Yan Yong-He (1253)

Shi Hu Ye Guang Wan (Dendrobium Pill for Night Vision)
From: Experiental Formulas from the Auspicious Balmboo Hall (1326)

Shi Quan Yu Zhen Tang (All-Inclusive Decoction for Fostering the True)
From: Essays on Medicine Esteeming the Chinese and Respecting the Western by Zang Xi Chun / Zang Shou Fu (1918-1934)

Shu Yu Wan (Dioscorea Pill)
From: Essentials from the Golden Cabinet by Zhang Zhong-Jing (c. 220)

Sou Feng Shun Qi Wan (Track Down Wind and Smooth the Flow of Qi Pill)
From: Fine Formulas for Women with Annotations and Commentary (16th Century)

Suo Quan Wan (Restrict the Fountain Pill)
From: Formulas Kept by the Wei Family (1227)

Tu Su Zi Wan (Cuscata Pill)
From: Formulas to Aid the Living by Yan Yong-He (1253)

Wan Dai Tang (End Discharge Decoction)
From: Fu Qing-Zhu's Women's Disorders by Fu Qing-Zhu (1826)

Wu Bi Shan Yao Wan (Incomparable Discorea Pill)
From: Important Formulas Worth a Thousand Gold Pieces by Sun Si Miao (650)

Xi Jiao Di Huang Tang (Rhinoceros Horn and Rehmannia Decoction)
From: Important Formulas Worth a Thousand Gold Pieces by Sun Si Miao (650)

Yi Huang Tang (Change Yellow [Discharge] Decoction)
From: Fu Qing-Zhu's Women's Disorders by Fu Qing-Zhu (1826)

You Gui Wan (Restore the Right [Kidney] Pill)
From: Collected Treatises of Jing-Yue by Zhang Jie Bin / Zhang Jing Yue (1624)

Yu Ye Tang (Jade Fluid Decoction)
From: Essays on Medicine Esteeming the Chinese and Respecting the Western by Zang Xi Chun / Zang Shou Fu (1918-1934)

Yue Hua Wan (Moonlight Pill)
From: Awakening of the Mind in Medical Studies by Cheng Guo-Peng (1732)

Zhi Bai Di Huang Wan (Anemarrhenae, Phellodendron and Rehmannia Pill)
From: Craft of Medicines and Patterns for Children by Qian Yi (1119)

Zi Shui Qing Gan Yin (Enrich Water and Clear the Liver Drink)
From: Externally Contracted Patterns from Xitang (1725)

Zuo Gui Wan (Restore the Left [Kidney] Pill)
From: Collected Treatises of Jing-Yue by Zhang Jie Bin / Zhang Jing Yue (1624)

Zuo Gui Yin (Restore the Left (Kidney) Drink)
From: Collected Treatises of Jing-Yue by Zhang Jie Bin / Zhang Jing Yue (1624)

Research Links & References: (click to display)

Individual Herbs Notebook

山 药  Shan Yao

Translation: Mountain Medicine

Pharmaceutical: Rhizoma Dioscoreae
Taxonomy: Dioscorea polystachya syn. batatas

Other names: Chinese Yam / Shu Yu

Category: Herbs that Tonify Qi

Research Links:

Reference Notes: