English: Eucommia bark

Chinese: 杜仲

Parts used: Dried stem bark

TCM category: Tonic herbs for Yang Deficiency

TCM nature: Warm

TCM taste(s): Sweet

Organ affinity: Kidney Liver

Scientific name: Eucommia ulmoides

Other names: Rubber tree bark

Use of Du Zhong (eucommia bark) 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 practitioner, they will be best able to guide you.

Preparation: Remove the bark from the tree and let it dry under the sun

Dosage: 6 - 12 grams

Main actions according to TCM*: Tonifies the Liver and Kidneys. Calms ascendant Liver Yang (hypertension/high blood pressure). Calms a restless fetus.

Primary conditions or symptoms for which Du Zhong may be prescribed by TCM doctors*: Lumbago Miscarriage Hypertension Fatigue Dizziness Headache

Contraindications*: This herb should not be used by those with Heat signs associated with Yin Deficiency; it should not be used in conjunction with Ningpo figwort root (Xuan Shen).

Common TCM formulas in which Du Zhong is used*

Zan Yu Dan

Source date: 1624 AD

Number of ingredients: 14 herbs

Formula key actions: Warms and tonifies the Kidneys.

Conditions targeted*: Erectile dysfunctionInfertility in male and others

Du Zhong is a king ingredient in Zan Yu Dan. Like the name indicates, it means it has more power than other ingredients in the formula.

In Zan Yu Dan, Du Zhong tonify the Kidneys and strengthen the Kidney Yang.

Read more about Zan Yu Dan

You Gui Wan

Source date: 1624 AD

Number of ingredients: 10 herbs

Formula key actions: Warms and tonifies Kidney Yang. Replenishes the Essence. Tonifies the Blood.

Conditions targeted*: Nephrotic syndromeOsteoporosis and others

Du Zhong is a deputy ingredient in You Gui Wan. This means it helps the king ingredient(s) treat the main pattern or it serves to treat a coexisting pattern.

Read more about You Gui Wan

An Tai Zhu Gao

Source date: 1879 AD

Number of ingredients: 14 herbs

Formula key actions: Strengthens the Qi and Blood. Tonifies the Liver and Kidneys. Calms the fetus.

Conditions targeted*: Restless fetus and others

Du Zhong is a deputy ingredient in An Tai Zhu Gao. This means it helps the king ingredient(s) treat the main pattern or it serves to treat a coexisting pattern.

In An Tai Zhu Gao, Du Zhong calms a restless fetus. 

Read more about An Tai Zhu Gao

Du Huo Ji Sheng Tang

Source date: 650 AD

Number of ingredients: 15 herbs

Formula key actions: Anti-rheumatic, clears Wind, Cold and Damp Stagnation. Strengthens the function of the Liver and Kidney. Tonifies Qi and Blood.

Conditions targeted*: Chronic lower back painSciatica and others

Du Zhong is an assistant ingredient in Du Huo Ji Sheng Tang. This means that it either serves to reinforces the effect of other ingredients or it moderates their toxicity.

Read more about Du Huo Ji Sheng Tang

Tian Ma Gou Teng Yin

Source date: 1958 AD

Number of ingredients: 11 herbs

Formula key actions: Calms the Liver. Extinguishes wind. Invigorates the blood. Clears heat. Tonifies the Liver and Kidneys.

Conditions targeted*: InsomniaHeadache and others

Du Zhong is an assistant ingredient in Tian Ma Gou Teng Yin. This means that it either serves to reinforces the effect of other ingredients or it moderates their toxicity.

In Tian Ma Gou Teng Yin, Du Zhong tonifies and nourishes the Liver and Kidneys in order to reinforce the root.

Read more about Tian Ma Gou Teng Yin

Da Fang Feng Tang

Source date: 1107 AD

Number of ingredients: 14 herbs

Formula key actions: Expel Wind Damp. Relieve pain. Tonify the Liver and the Kidneys. Tonify the Blood and Qi.

Conditions targeted*: ArthralgiaCommon cold and others

Du Zhong is an assistant ingredient in Da Fang Feng Tang. This means that it either serves to reinforces the effect of other ingredients or it moderates their toxicity.

In Da Fang Feng Tang, Du Zhong warms and tonifies the Liver as well as the Kidneys. It also strengthens the Channels, bones and tendons. 

Read more about Da Fang Feng Tang

He Che Da Zao Wan

Number of ingredients: 11 herbs

Formula key actions: Tonifies the Kidneys. Strengthens the Directing and Penetrating Vessels. Regulates the periods.

Read more about He Che Da Zao Wan

Da Bu Yuan Jian

Source date: 1624 AD

Number of ingredients: 8 herbs

Formula key actions: Tonifies Yin and Blood. Nourishes Qi and Yang.

Conditions targeted*: Uterine prolapse and others

In Da Bu Yuan Jian, Du Zhong tonifies Kidney Yang and strengthen the back

Read more about Da Bu Yuan Jian

Da Ying Jian

Source date: 1624 AD

Number of ingredients: 7 herbs

Formula key actions: Tonifies Qi and Blood. Expels Cold.

In Da Ying Jian, Du Zhong tonifies Kidney Yang

Read more about Da Ying Jian

Dang Gui Di Huang Yin

Source date: 1640 AD

Number of ingredients: 7 herbs

Formula key actions: Nourishes Blood. Tonifies Kidney and Liver Yin. Regulates the menstrual cycle.

In Dang Gui Di Huang Yin, Du Zhong tonifies and warms Kidney Yang

Read more about Dang Gui Di Huang Yin

Qing E Wan

Source date: 1107

Number of ingredients: 3 herbs

Formula key actions: Warms and Reinforces Kidney Yang.

Read more about Qing E Wan

Key TCM concepts behind Du Zhong's properties

In Traditional Chinese Medicine (TCM), Du Zhong belongs to the 'Tonic herbs for Yang Deficiency' category. Tonic herbs are used for patterns of Deficiency, when one lacks one of the 'Four Treasures' (Qi, Blood, Yin and Yang). Yang Tonics are generally used in combination with a small amount of Yin tonics. If Yin is deficient, neither Qi nor Yang herbs alone will be effective. The most common symptoms associated with Yang Deficiency are low libido and impotence. It is worth mentioning that another very effective remedy against Yang Deficiency is regular exercise.

Furthermore Du Zhong is Warm in nature. This means that Du Zhong tends to help people who have too much 'Cold' in their body, although with less effect than a plant that would be Hot in nature. Balance between Yin and Yang is a key health concept in TCM. Those who have too much Cold in their body are said to either have a Yin Excess (because Yin is Cold in nature) or a Yang Deficiency (Yang is Hot in Nature). Depending on your condition Du Zhong can help restore a harmonious balance between Yin and Yang.

Du Zhong also tastes Sweet. The so-called 'Five Phases' theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Sweet ingredients like Du Zhong tends 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 Du Zhong is thought to target the Kidney and the Liver. According to TCM, 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 on the other hand is often referred as the body's "general" because it is in charge of regulating the movements of Qi and the Body Fluids. It also takes a leading role in balancing our emotions.

Research on Du Zhong

Standardized Eucommia extract reduces blood pressure and has beta-adrenergic blocking activity.1

The extracts of Eucommia showed anti-hypertensive, anti-complementary, anti-oxidative, and anti-gastric ulcer effects, and promoting collagen synthesis, accelating granuloma formation, and other pharmacological effects.2

Bushen Qiangdu Recipe (consisting of eucommia bark) showed significant effect in treatment of ankylosing spondylitis.3

Sources:

1. Greenway F, Liu Z, Yu Y, Gupta A. (2011). A clinical trial testing the safety and efficacy of a standardized Eucommia ulmoides Oliver bark extract to treat hypertension. Altern Med Rev. , 16(4):338-47.

2. Deyama T, Nishibe S, Nakazawa Y. (2001). Constituents and pharmacological effects of Eucommia and Siberian ginseng. Acta Pharmacol Sin. , 22(12):1057-70.

3. Wang H, Yan XP, Kong WP. (2011). Effect of bushen qiangdu recipe on osteoporosis and bone loss of patients with ankylosing spondylitis. Zhongguo Zhong Xi Yi Jie He Za Zhi. , 31(4):471-5.