Unprepared Rehmannia

Chinese: 地黄

Pinyin: Dì Huáng

Parts used: Prepared dried root tuber

TCM category: Herbs that cool the Blood

TCM nature: Cold

TCM taste(s): Sweet

Meridian affinity: HeartKidneyLiver

Scientific name: Rehmannia glutinosa

Use of unprepared rehmannia (Dì Huáng) in TCM

Please note that you should never self-prescribe TCM ingredients. A TCM ingredient is almost never eaten on its own but as part of a formula containing several ingredients that act together. Please consult a professional TCM practitionner, they will be best able to guide you.

Preparation: Remove impurities, wash, cut in thick slices and dry.

Dosage: 9 - 30 grams

Main actions according to TCM*: Expels Heat by Cooling Blood. Tonifies Yin by promoting Fluid production. Soothes the Heart by calming Blazing Fire. Cools and nourishes.

Primary conditions or symptoms for which unprepared rehmannia may be prescribed by TCM doctors*: Palpitations Nosebleed Fever Insomnia Diabetes Dermatitis

Contraindications*: This herb should not be used by those with Spleen Qi or Yang Deficiency especially when there is Dampness in conditions such as diarrhea, lack of appetite or Excess Phlegm. It should also be avoided by pregnant women.

Common TCM formulas in which unprepared rehmannia are used*:

Key TCM concepts behind unprepared rehmannia's properties

In Traditional Chinese Medicine (TCM), unprepared rehmannia are plants that belong to the 'Herbs that cool the Blood' category. Herbs in this category are used to clear inflammatory and infectious conditions, referred to as 'Internal Heat' in TCM. This is why most of the herbs in this category will have both antibacterial and antiviral properties. In TCM one has too much 'Heat' in their body as a result of a deficiency of 'Yin' (which is Cold in nature, see our explanation on Yin and Yang) or, more commonly, an excess of Yang (Hot in nature). Herbs that cool the Blood treat the latter and as such tend to be Cold or Neutral in nature.

As suggested by its category unprepared rehmannia are plants that are Cold in nature. This means that unprepared rehmannia typically help people who have too much "heat" in their body. Balance between Yin and Yang is a key health concept in TCM. Those who have too much heat in their body are said to either have a Yang excess (because Yang is Hot in nature) or a Yin deficiency (Yin is Cold in Nature). Depending on your condition unprepared rehmannia can help restore a harmonious balance between Yin and Yang.

Unprepared Rehmannia also taste Sweet. The so-called "five elements" theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Sweet ingredients like unprepared rehmannia tend to slow down acute reactions and detoxify the body. They also have a tonic effect because they replenish Qi and Blood.

The tastes of ingredients in TCM also determine what organs and meridians they target. As such unprepared rehmannia are thought to target the Heart, the Kidney and the Liver. In addition to regulating blood flow, in TCM the Heart is believed to be the store of the "spirit" which basically refers to someone's vitality. The Kidneys do not only regulate the urinary system but also play a key role in the reproductive system and the growth and aging process of the body. The Liver is often referred as the body's "general" because it is in charge of regulating the movements of Qi and body fluids. It also takes a leading role in balancing our emotions.

Research on unprepared rehmannia

Shufeng Liangxue Decoction (consisting of rehmannia root) is effective and safe in treating hormone dependence dermatitis.1

Ziyin Tongbi Decoction (consisting of rehmannia root) is effective and safe for the treatment of benign prostatic hyperplasia.2

Sources:

1. Bai YS, Zhou CY, Wang JQ. (2008). Clinical observation on auxiliary treatment of hormone dependence dermatitis by shufeng liangxue decoction. Zhongguo Zhong Xi Yi Jie He Za Zhi. , 28(12):1121-3.

2. Guo J1, Song CS, Han Q. (2008). Clinical observation on ziyin tongbi decoction in treating benign prostatic hyperplasia. Zhongguo Zhong Xi Yi Jie He Za Zhi. , 28(12):1082-5.