Dioscorea (Radix Dioscoreae; Shan Yao)


TCM Herbal Story

Dioscorea (Radix Dioscoreae; Shan Yao)

Long ago, there were two countries at war, where the weaker one was defeated by the stronger one.  The army of the stronger nation not only routed the army of their enemy, but also took over a lot of their lands, leaving them with only a thousand troops.  In order to survive, the remaining troops had no choice but to escape into a mountain for shelter.  However, the army of the stronger nation followed them to the foot of the mountain and made several attempts for attack.  After several failure attempts due to the steep terrain, the army decided to surround the mountain instead, believing that their enemy would either run out of food and surrender, or starve to death.


When there were no signs of the army of their enemy after two months, the commander of the stronger nation believed that their enemy should have not much food supply left and was about to surrender.  When there were still no signs of the army of their enemy after four months, the commander just assumed that their enemy had started to slaughter their horses for the source of food.


After six months, the commander believed that the enemy had eaten all their horses and would soon starve to death.  He asked soldiers to shout out to their enemy, telling them to give up and stop struggling, but their enemy only shot out some arrows in return.  By the eighth month, the commander assumed that more than half of their enemy had died and let down their defenses, as their enemy was no longer posed as a threat.


One night, when the army of the stronger nation was sounded asleep, they were attacked by a powerful troop coming out of nowhere.  Surprised and unprepared, they were defeated by this powerful troop.


This powerful troop turned out to be the troops from the weaker nation that were trapped in the mountain.  The soldiers found a plant in the mountain with root that shaped like a rod, and had white or light green flower that blossomed in the summer.  With this plant as the food source, they were well rested and trained during the past several months.  Therefore, instead of being starve to death like expected, they had regrouped into an organized and powerful troop, and successfully ambushed the army of the stronger nation.


The plant was named “Shan Yu”, which meant “meeting in the mountains”, since it was discovered when the soldiers were short of food during their time in the mountains.  Later on, people began to use this plant as a source of food and found that it could strengthen the spleen, stomach, lung, and kidney.  As a result, the plant was renamed as “Shan Yao”, meaning “medicine of mountain” for its benefits to health.


Dioscorea is the root of Dioscorea opposita Thunb. Its properties are sweet and neutral.  In enters through the kidney, lung, and spleen.



Actions & Indications:

  • Tonifies and augments the Spleen and Stomach
  • Tonifies the Lung qi and augments the Lung yin
  • Tonifies the Kidneys and also stabilizes and binds

Caution & Contradiction

  • Contraindicated in cases of excess, especially when there is fullness due to dampness, stagnation, or accumulation.
  • According to some traditional sources, this herb antagonizes Radix Euphobiae kansui (Gan Sui).


The original article is from Brion Research Institute, translated by Sun Ten Pharmaceutical Co., Ltd.

For Chinese/original version, please go to:


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