Dioscorea polystachya, Shan Yao 山药 Chinese Yam
Shan Yao (TCM)
Dioscorea alata
Descourtilz, Flore médicale des Antilles, 1829
Dioscorea polystachya
(Photo by James H. Miller) (Wikimedia)
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Botanical name:
Dioscorea spp.
D. polystachya is the standard species. Also used are D. persimilis, D. alata, D. fordii, D. batatas
A number of texts list D. opposita, but this is apparently incorrect.
Parts used:
Rhizome
Temperature & Taste:
Neutral, slightly moist. Sweet
Uses:
1. Tonifies Spleen and Stomach:
-low energy, poor appetite, loose stool, spontaneous sweating
-tonic for the young and old; eaten as a health food in China
-“replenishes the Spleen and Stomach, stops diarrhea” (Li Shi Zhen)
2. Tonifies Lung Qi and Yin:
-chronic cough, wheezing
3. Tonifies Kidneys, Astringes Kidneys:
-Diabetes, Wasting and Thirsting Disorder (overlaps Diabetes)
-Urinary frequency, nocturnal Urination
-Spermatorreha, Leukorrhea
-“reinforces physical strength … and enhances male sexuality” (Shen Nong Ben Cao)
-“Long-term use brightens the eye and improves hearing”. (Shen Nong Ben Cao)
-“enlightens one’s wisdom and enhances one’s memory”. (Zhen Quan)
Dose:
Decoction: 9–30 grams; when used alone or in extreme weakness and for Wasting and Thirsting (Diabetes-like disorders), up to 60–250 grams are used per day.
Powder: 3–10 grams
The fresh root is often added to Soups in China as a health tonic and biscuits are also made to support children’s health.
Main Combinations:
The 3 Kidney Medicines
Often Dioscorea Shan Yao is combined with Cornus Shan Zhu Yu and Rehmannia Shu Di Huang. This trio forms the basis of the most important formulas used to strengthen the Kidneys. Alone, they nourish Kidney Yin and are usually corrected with the addition of Poria Fu Ling, Alisma Ze Xie and Paeonia Mu Dan Pi (as in Liu Wei Di Huang Wan, ‘Rehmannia ‘). When combined with Cinnamon (Rou Gui) and Aconitum Fu Zi, it is called Shen Qi Wan (Kidney Qi Pill) and is used for Yang deficiency.
1. Spermatorrhea and Night-sweats with Kidney Yin deficiency, Dioscorea Shan Yao with … available in PRO version
2. Spleen and Stomach deficiency:
i. with poor energy and poor appetite, Dioscorea Shan Yao with … available in PRO version
ii. with Qi stagnation, Dioscorea Shan Yao with … available in PRO version
iii. with loose stool or diarrhea, Dioscorea Shan Yao with … available in PRO version
iv. with Food Stagnation, Dioscorea Shan Yao with … available in PRO version
v. Weakness, fatigue, poor appetite, Loose stool from, Dioscorea Shan Yao with … available in PRO version
4. Chronic Cough from Lung Qi and Yin deficiency, Dioscorea Shan Yao with … available in PRO version
5. Chronic Cough with Lung Qi deficiency, Dioscorea Shan Yao with … available in PRO version
6. Leukorrhea:
i. with Blood, Dioscorea Shan Yao with … available in PRO version
ii. Damp-heat with Spleen deficiency, Dioscorea Shan Yao with … available in PRO version
Major Formulas:
Liu Wei Di Huang Wan
Zhi Bai Di Huang Wan
Shen Ling Bai Zhu San
Shen Qi Wan, Jin Gui Shen Qi Wan
You Gui Wan
You Gui Yin
Zuo Gui Wan
Zuo Gui Yin
Cautions:
Generally very safe and regarded as a Health Food.
Not used alone when there is accumulated Dampness in the abdomen.
