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Eucommia bark

Eucommia ulmoides · 杜仲

Herbs & Roots. Chinese Medicine.

Also called Du zhong, Hardy rubber tree, Chinese rubber tree

Pinyin: Dù Zhòng

May lower blood pressure

The bark of a tree whose sap contains rubber. Chinese medicine uses it to strengthen the lower back, knees and bones.

Did you know? The bark, leaves and twigs of the eucommia tree contain a rubber-like sap, which is why it is called the hardy rubber tree.

What it may help, and how strong the proof is

Blood pressure. Lab and animal studies suggest a blood pressure effect. Human proof is limited.
Traditional proof
Bones. Traditional use to strengthen bones. Few small human studies, mostly of formulas.
Traditional proof
Joint pain & arthritis. Traditional use for weak knees and lower back. No good human trials test the bark alone.
Traditional proof

Parts of the body

Heart & vessels, Bones, Joints

Traditional use

Traditional Chinese Medicine uses du zhong to tonify Kidney yang (warming vital energy) and strengthen the lower back, knees and bones. It is part of Du Huo Ji Sheng Tang (Angelica and Loranthus Decoction) and You Gui Wan (Restore the Right Kidney Pill).

How it is classified

Herbal actions: Tonic, Nutritive, Analgesic. Energy: warming.
Chinese medicine: 杜仲 Tonify yang. Nature: warm. Flavour: sweet, pungent. Enters the Liver and Kidney channels.

How people take it

Traditional decoctions often use 6 to 12 g of bark. Leaf tea and capsules are common. No strong human dose data exist.

Decoction, tea, capsule and powder.

Where to get it

Cultivated mainly in China. Sold as dried bark slices, leaf tea, powder and capsules.

Be careful

Usually mild. Dizziness or stomach upset are possible but uncommon. Because it may lower blood pressure, people on blood pressure medicine should check with a clinician.

Avoid if: pregnancy; low blood pressure.

Mixing with other things

Works well together
Du zhong and niu xi (achyranthes) are both in Du Huo Ji Sheng Tang for lower back and knee weakness.
Works well together
Du zhong and tu si zi are both in You Gui Wan (Restore the Right Kidney Pill).
Works well together
Du zhong and goji are both in You Gui Wan.
Works well together
Yin yang huo and du zhong are both used for lower back and knee weakness in tradition.
Works well together
Rou cong rong and du zhong are both used for the lower back and kidneys in tradition.
Use caution
Blood pressure medicine (lisinopril, amlodipine, losartan)
Eucommia may lower blood pressure. Combined with blood pressure medicine, the effect may be too strong. Monitor readings.

Adds up with others that may lower blood pressure: , , , , , , , , , , , , , and 12 more.

The honest take

Eucommia is a traditional bark for back, knee and bone strength. Most of the evidence is lab and animal work, and human trials mostly test it inside formulas. It is low risk for many people, but its blood pressure effect is worth watching.