 Dioscorea (Shanyao)
/Chinese Yam
Pharmaceutical Name: Rhizoma Dioscoreae
Botanical Name: Dioscorea opposita Thunb.
Common Name: Chinese yam, Dioscorea
Source of Earliest Record: Shennong Bencao
Jing
Part Used & Method for Pharmaceutical
Preparations: The rhizomes are dug in the
period of Frost's Descent (eighteenth solar
term). After the rough bark has been removed,
the rhizomes are cleaned and dried in either
the sun or the shade. Then, they are soaked
again and cut into slices.
Properties & Taste: Sweet and neutral
Meridians: Spleen, lung and kidney
Functions: 1. To strengthen the spleen and
stomach; 2. To tonify the lungs and kidneys
Indications & Combinations:
1. Weakness of the spleen and stomach manifested
as poor appetite, diarrhea and lassitude.
Dioscorea (Shanyao) is used with Ginseng (Renshen),
White atractylodes (Baizhu) and Poria (Fuling)
in the formula Shen Ling Baizhu San.
2. Excessive dampness due to deficiency
of the spleen manifested as whitish and dilute
leukorrhagia and lassitude. Dioscorea (Shanyao)
is used with White atractylodes (Baizhu),
Poria (Fuling) and Euryale seed (Qianshi).
3. Excessive dampness transforming into
heat manifested as yellow leukorrhea. Dioscorea
(Shanyao) is used with Phellodendron bark
(Huangbai) and Plantain seed (Cheqianzi) in
the formula Yihuang Tang.
4. Leukorrhagia due to deficient kidneys
manifested as leukorrhagia and lower back
pain. Dioscorea (Shanyao) is used with Dogwood
fruit (Shanzhuyu) and Dadder seed (Tusizi).
5. Diabetes manifested as extreme thirst,
excessive drinking, excessive food intake,
profuse urination and lassitude. Dioscorea
(Shanyao) is used with Astragalus root (Huangqi),
Trichosanthes root (Tianhuafen), Fresh rehmannia
root (Shengdihuang) and Pueraria root (Gegen)
in the formula Yuye Tang.
6. Nocturnal emissions due to deficient
kidneys. Dioscorea (Shanyao) is used with
Dogwood fruit (Shanzhuyu) and Prepared rehmannia
root (Shudihuang) in the formula Liuwei Dihuang
Wan.
7. Frequent urination due to kidney deficiency.
Dioscorea (Shanyao) is used with Bitter cardamom
(Yizhiren) and Mantis egg case (Sangpiaoxiao).
8. Chronic cough due to deficient lungs.
Dioscorea (Shanyao) is used with Glehnia root
(Shashen), Ophiopogon root (Maidong) and Schisandra
fruit (Wuweizi).
Dosage: 10-30 g; 6-10 g (for powder)
Cautions & Contraindications: This herb
is contraindicated during food retention.
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