IngredientsEucommia ulmoides is the sole living species of the genus Eucommia. Eucommia is the only genus of the family Eucommiaceae, which was formerly considered a separate order, Eucommiales. It is a perennial deciduous tree belonging to the Eucommiaceae family and is a unique species native to China. The plant is known by numerous common names: it is known as "Du Zhong" in Chinese. In Japanese, the plant is commonly called Tochu, and its bark is referred to as Cortex Eucommiae in pharmacopeial contexts. It is also sometimes known as the "gutta-percha tree" or "Chinese rubber tree," but is not related to either the true gutta-percha tree of southeastern Asia nor to the South American rubber tree.
It is considered vulnerable in the wild, but is widely cultivated in China for its bark and is highly valued in herbology such as traditional Chinese medicine. The tree grows to about 15 m tall. It is a tertiary relict plant species that remains the only extant representative of both the genus Eucommia and the family Eucommiaceae. It is occasionally planted in botanical gardens and other gardens in Europe, North America, and elsewhere, being of interest as the only cold-tolerant (to at least −30 °C) rubber-producing tree. Fossils of other Eucommia species have been found in 10- to 35-million-year-old brown coal deposits in central Europe and widely in North America, indicating the genus had a much wider range in the past.
Once widespread in the Northern Hemisphere, it disappeared from other parts of Europe and North America due to the Quaternary Ice Age and survives only in China. As the utility and value of E. ulmoides has been recognized, its planting has been expanded; the main production areas now include the central and northern subtropical and southern temperate zones of China, and it has been successfully introduced to the United States, Britain, France, Hungary, Russia, Japan, Korea, and other countries.
The bark, leaves, seeds, and even the male flowers are commonly utilized as medical remedies and are subjects of pharmacological investigation. While current research has predominantly focused on the bark and leaves, other parts, such as flowers, seeds, stems, and roots, remain underexplored despite their substantial potential for medicinal and edible applications.
The bark (pharmacopeial name: Cortex Eucommiae) is harvested in a specific way. Bark strips are harvested in April when they are most easily peeled off the tree. They are bundled up, placed under straw for a week to sweat, then sun-dried until the inner bark can be peeled off the outer. Historically, only the bark was used medicinally, requiring 15 to 20 years of tree growth before harvest.
Common preparations include decoctions (water extracts), standardized dry extracts (often standardized to a percentage of pinoresinol diglucoside or chlorogenic acid), encapsulated powders, and herbal teas. A tea made from Eucommia ulmoides leaves and bark is part of the Japanese diet. In Japan, Du Zhong tea made from the leaves became extremely popular beginning in the 1980s as a health beverage for blood pressure support. The Chinese Pharmacopoeia specifies quality markers: the content of (+)-pinoresinol di-O-β-D-glucopyranoside should be higher than 0.1% in Eucommia ulmoides bark extract, while chlorogenic acid should be higher than 0.08% for Eucommia ulmoides leaf according to the Chinese Pharmacopoeia (2020 edition).
The leaf and bark of E. ulmoides are officially documented in the Chinese Pharmacopoeia. The leaf (Du Zhong Ye) was officially included in the Chinese Pharmacopoeia in 2005, and in 2023 it was added to the national "food and medicine dual-use" list.
Du Zhong has one of the longest documented histories of any Chinese medicinal herb, first recorded as an upper-grade herb in the Shen Nong Ben Cao Jing over 2,000 years ago. The Shen Nong's Herbal Classic (c. 300 AD), the earliest pharmacopoeia in China, includes 365 herbal medicines, and Cortex Eucommiae was classified as a top-grade crude herbal drug. The earliest medical record about the bark of Eucommia ulmoides was found in the Zhi Bai Bing Fang in the Han Dynasty, which was about the treatment of internal injuries caused by consumptive diseases.
The Chinese medical book Compendium of Materia Medica (Ben Cao Gang Mu), edited by Li Shizhen during the Ming Dynasty (1600), mentions Cortex Eucommiae. This book also describes fresh Eucommia leaf as having been "consumed as a vegetable." In 1590, it was reported in Ben Cao Gang Mu to enhance the kidney, bones, and tendons. The famous Ming Dynasty physician Li Shizhen expanded classical understanding by highlighting that Du Zhong is not merely a Kidney tonic, crediting the Jin Dynasty physician Wang Haogu with identifying it as a Liver channel herb that "moistens Liver dryness and supplements Liver deficiency."
The medicinal functions of Eucommia leaves, flowers, fruits, and stems were described as similar to those of the bark, expounded in the pharmaceutical book Ben Cao Tu Jing in the Song Dynasty. The pivotal shift came in the Song and Jin-Yuan periods, when practitioners first recognized that the leaves, flowers, and fruit had therapeutic effects similar to the bark.
Within the framework of Traditional Chinese Medicine (TCM), extracts of the aerial parts of this plant have been widely used in famous botanical tonics and antirheumatic supplements for more than 2,000 years, and people believe it can "nourish the kidney and reinforce the Yang." It can be used alone or mixed with other compounds in the prescription of TCM to treat impotence, spermatorrhoea, prospermia, forgetfulness, osteoporosis, menopause syndrome, hypertension, rheumatoid arthritis, lumbago, ischialgia, aching knees, kidney deficiency pain, weak bones, bone fractures and joint diseases, and lower back pain.
In East Asia, especially in China, Korea, and Japan, Eucommia ulmoides is widely used as a traditional medicine with a long history of safety for its kidney-tonifying function. It is used to cure lumbago associated with kidney deficiency and to promote human longevity. Several ethnic groups in China use Eucommia in medicine, and the application of using it to treat hypertension, nourish the liver and kidneys, and strengthen the muscles and bones is consistent with the record in the Chinese Pharmacopoeia.
The bark of E. ulmoides (Cortex Eucommiae) has been traditionally used as an analeptic, analgesic, sedative, antihypertensive, and diuretic. In TCM, it has been used for the treatment of various diseases since ancient times, involving lumbar pain, knee pain, osteoporosis, hepatoprotection, paralysis, intestinal haemorrhoids, vaginal bleeding, abortion, spermatorrhoea, foot fungus, and anti-aging.
The leaf, stem, and bark as well as the staminate flower of Eucommia ulmoides have been traditionally used to cure many diseases in China, Japan, and Korea, among others. In Japan, the plant is known as Tochu. Eucommia ulmoides (Tochu) bark has historically been used as herbal medicine, while the leaves have been used as food materials. The leaf tea became a mainstream health product in Japan from the 1980s onward, primarily for cardiovascular and blood pressure support.
Modern research shows that different parts of E. ulmoides (bark, leaves, flowers, seeds) contain various chemical components, including lignans, iridoids, phenylpropanoids, flavonoids, terpenoids, steroids, polysaccharides, and other compounds. So far, 246 compounds have been isolated from E. ulmoides.
Extensive studies of the chemical components of Eucommia ulmoides have led to the identification of compounds including lignans, iridoids, phenolics, steroids, terpenoids, and flavonoids. Among these, lignans and iridoids are the two major constituents and are important chemotaxonomic markers.
Lignans are a kind of natural product formed by oxidative polymerization of two molecules of phenylpropanoid derivatives (C6–C3 monomers). Most lignans exist in Cortex Eucommiae in the form of β-D-glucopyranoside compounds. Studies have shown that lignans and their derivatives are the most studied compounds in E. ulmoides, with the clearest structure and the most definite components.
The primary lignan of pharmacological relevance is (+)-pinoresinol di-O-β-D-glucopyranoside (also called pinoresinol diglucoside, PG or PDG). The main lignan components, liriodendrin, (+)-pinoresinol di-O-β-D-glucopyranoside, and (+)-syringaresinol, have been shown to have anti-hypertensive effects. In the Chinese Pharmacopoeia (2010 edition), pinoresinol di-O-β-D-glucopyranoside was used as the quality control marker for Eucommia ulmoides bark by HPLC, and chlorogenic acid was used as the quality control marker for the leaf.
Aucubin and geniposide, both belonging to the iridoid class, have been extensively and profoundly studied for their biological activities, including anti-hypertension, anti-diabetes, neuroprotection, anti-cancer, anti-inflammatory, anti-osteoporotic, hepatoprotection, and kidney protection. Aucubin, genipin, and geniposidic acid — the main components of iridoids — exhibit anti-hypertensive and anti-aging properties. Geniposidic acid (GEA), an iridoid glycoside, has been identified as one of the important components of pharmacological relevance in the plant.
Aucubin has been reported to exhibit strong anti-osteoporotic activity, as it can increase the differentiation of osteoblasts, promote the increase of cortical bone thickness and bone density, and prevent the apoptosis of osteoclasts.
Chlorogenic acid is the major phenolic acid and quality-control marker for the leaf. Chlorogenic acid possesses good medical translational potential with anti-obesity, anti-diabetes, anti-hypertension, anti-metabolic syndrome, and anti-microbial activities. Chlorogenic acid, a prominent phenolic constituent, exhibits potent antioxidant and hypoglycemic properties through free radical scavenging and the modulation of enzymatic pathways. Antibacterial, antioxidant, and antimutagenic activity are also associated with chlorogenic acid.
Antioxidant, anti-inflammatory, and antiviral activity are associated with the flavonoids found in E. ulmoides, which include baicalein, wogonin, and oroxylin A. In the male flower alone, targeted HPLC-MS analysis identified 125 flavonoids and flavanols, 32 flavanones, 22 isoflavonoids, 11 chalcones and dihydrochalcones, and 17 anthocyanins. Other flavonoids identified across plant parts include quercetin, kaempferol, naringenin, rutin, hyperoside, and astragalin.
The plant is rich in diverse bioactive compounds, including lignans, iridoids, flavonoids, polysaccharides, E. ulmoides gum (a natural polyisoprene rubber), amino acids, and minerals. Eucommia ulmoides is a rubber-producing plant, although not the source of gutta-percha as its common name might imply. Geniposidic acid, another principal compound, displays marked effectiveness in neutralizing free radicals, mediating anti-inflammatory processes, regulating apoptosis, and conferring neuroprotection.
Eucommia is an herbal medicine that, by increasing nitric oxide, has been shown to reduce blood pressure in rats and humans. The lignan fraction (particularly pinoresinol diglucoside) appears to be a primary driver of this vasodilatory effect. Since the 1970s, the main pharmacologically active compound for anti-hypertensive activities of E. ulmoides has been identified as (+)-pinoresinol di-β-D-glucoside (PG). A systems pharmacology study using oral bioavailability prediction and network pharmacology techniques successfully identified 41 candidate compounds contained in Eucommia ulmoides and 39 potential targets, helping to uncover the synergistic mechanism of action of the plant at a systems level.
Eucommia cortex extract can be used in the control of osteoporosis because Eucommia extract is actively involved in mechanisms which initiate osteoblast activity, enhance osteogenesis, decrease osteoclast activity, and thus prevent osteolysis. Network pharmacology enrichment analysis suggests that iridoid glycosides of Eucommia ulmoides prevent osteoporosis mainly through the PI3K-Akt signaling pathway, MAPK signaling pathway, and estrogen signaling pathway.
The bioactive components contribute to anti-inflammatory, antioxidant, antihypertensive, immunomodulatory, and bone-protective effects. In a mouse model of ischemic stroke, water extract of E. ulmoides was shown to inhibit neuroinflammation induced by ischemic stroke by alleviating microglial activation and inhibiting the activity of the TLR4/p38 MAPK and NF-κB pathways.
The male flowers of E. ulmoides, like the leaf and bark, contain many bioactive components including lignans, megastigmane glycosides, iridoids, phenolics, and flavonoids, which have typically exhibited neuroprotective, antioxidant, anti-tumor, anti-inflammatory, and anti-hypertensive activities.
Administration of E. ulmoides aqueous extract in diabetic osteoporosis mice eliminates oxidative stress by regulating the Nrf2/HO-1 pathway, and this promoted TRPV5/CaBP-D9k/PMCA-1b signaling in the intestine and kidney, which maintained calcium homeostasis. Active compounds abundant in E. ulmoides, including asperuloside, geniposidic acid, quercetin, chlorogenic acid, and aucubin, possess strong lipid-lowering effects.
This is the most clinically investigated area for E. ulmoides, and the area with the strongest accumulated evidence, though the overall clinical database remains relatively small.
Human clinical evidence: A controlled clinical trial was conducted to evaluate an aqueous bark extract of Eucommia standardized to eight percent pinoresinol di-beta-D-glucoside for blood pressure reduction in humans. Twenty-four healthy adult subjects with a blood pressure between 120–160/80–100 mmHg were randomized to Eucommia extract 500 mg three times daily for eight weeks, with 24-hour ambulatory blood pressure monitoring utilized at baseline and after eight weeks.
A 2025 exploratory single-arm clinical trial examined the effects of leaf extract on blood pressure. This exploratory single-arm clinical study was conducted on 17 participants including those with mild chronic kidney disease (CKD) (n = 9), who were administered a tablet product containing Tochu leaf extract for a short period (median: 33 days). Mean systolic blood pressure of all participants significantly decreased from 128.3 ± 12.3 mmHg at the start to 123.8 ± 10.2 mmHg at the end of the administration (p < 0.05). Analysis of CKD patients alone revealed that systolic blood pressure decreased to a greater extent, from 130.7 ± 12.9 mmHg to 121.2 ± 10.7 mmHg (p < 0.01), while the change in non-CKD patients was not significant.
An earlier uncontrolled Russian trial also documented a blood pressure effect: a non-controlled Russian trial documented a 25/14 mmHg drop in blood pressure in human subjects with hypertension treated with E. ulmoides tea.
In clinical settings, anti-hypertensive effects of Eucommia ulmoides leaves have been well documented. However, the clinical trials conducted to date have used small sample sizes, short durations, or lacked full randomization and placebo controls. The overall strength of human clinical evidence is preliminary to moderate: results are directionally consistent but larger, rigorously controlled trials are still needed.
Eucommia ulmoides Oliver is one of the commonly used traditional Chinese medicines for the treatment of osteoporosis, and iridoid glycosides are considered to be its active ingredients against osteoporosis.
Pre-clinical evidence: Total glycosides from Eucommia ulmoides seed (TGEUS) have been shown to improve bone density and femur strength in rats. Daily administration of TGEUS at the rate of 400 mg/kg body weight/day to normal and Dawley rats was reported to significantly increase bone mineral density and show improvements in microarchitecture structure of the femur bone. In vitro studies showed that crude water extract of Eucommia ulmoides enhanced proliferation of osteoblast-like cells by 45% when used at a concentration of 0.4 mg/mL in 48-hour co-cultures with UMR106 cells.
A 2025 scoping review summarized ninety studies on the topic. Ninety studies met the inclusion criteria for the review, and the evidence demonstrates that Eucommia ulmoides and its bioactive compounds — most notably aucubin, geniposide, rutin, and pinoresinol diglucoside — consistently promote osteoblastogenesis and inhibit osteoclastogenesis. The findings underscore the necessity for future research to prioritise standardised extract preparation, detailed pharmacokinetic studies, and rigorous, large-scale clinical trials to definitively establish its efficacy and safety in humans.
Evidence strength: primarily pre-clinical (in vitro and animal); mechanistic understanding is robust but human clinical trial data are currently lacking.
Modern pharmacological studies reveal remarkable therapeutic effects of E. ulmoides in hypertension, hyperglycemia, diabetes, and obesity. It has been shown to positively affect blood pressure, hyperlipidemia, oxidative stress, hyperglycemia, and obesity in experimental systems.
An animal study demonstrated that Eucommia leaf extract (ELE) prevents ovariectomy-induced osteoporosis and obesity in rats. Regarding the anti-diabetic mechanism, one study aimed to explore the bone protective effect of aqueous extract of Eucommia ulmoides in diabetic osteoporosis mice; DOP mice were established using a high-sugar, high-fat diet and streptozotocin (35 mg/kg for three consecutive days), and the EUL aqueous extract (2.5 g/kg/day) was orally administered for 6 weeks.
Evidence strength: predominantly animal and in vitro. Human interventional studies specifically targeting glycemic control or obesity with E. ulmoides as primary intervention are limited as of the most recent literature.
Eucommia ulmoides is widely used as a traditional Chinese herb to treat various neurodegenerative disorders. The aqueous extract of E. ulmoides exhibits significant neuroprotective effects in several experimental models, making it a potential therapeutic drug in the treatment of neurodegenerative diseases such as Alzheimer's disease.
In a zebrafish Alzheimer's disease model, researchers investigated whether extracts of E. ulmoides male flower (EUMF) have therapeutic effects against Alzheimer's disease. They focused on flavonoids of EUMF, identifying 125 flavonoids and flavanols, 32 flavanones, 22 isoflavonoids, 11 chalcones and dihydrochalcones, and 17 anthocyanins, and then tested the anti-AD effects using a zebrafish AD model.
In a mouse stroke model, supplementation with water extract of E. ulmoides bark was shown to significantly decrease infarct volume and ameliorate neurological dysfunction in mice following middle cerebral artery occlusion/reperfusion injury.
Evidence strength: early-stage, primarily pre-clinical (cell models, zebrafish, rodent). No controlled human clinical trials in neurological disease indications have been identified.
One study employed C. elegans as a model organism to evaluate the effects of Eucommia ulmoides leaf extract on lifespan and healthspan, aiming to elucidate its anti-aging activity and provide a scientific foundation for its application in functional foods and natural anti-aging therapeutics. Eucommia ulmoides leaf shows considerable promise in facilitating healthy aging. Supplementation with the extract significantly prolonged the lifespan of C. elegans by up to 14.69% and improved healthspan by alleviating age-related muscle deterioration, preserving intestinal barrier function, and regulating mitochondrial homeostasis.
Evidence strength: invertebrate model organism only; highly preliminary with respect to human relevance.
Eucommia ulmoides was traditionally used to reinforce the Kidney Yang and to treat "coldness" and male impotence. In a preclinical study, intragastric administration of Eucommia ulmoides at a dosage of 400 mg/kg in rats for 4 weeks notably increased catching frequency of the rats and enhanced expression of certain neuronal markers. Studies of the staminate (male) flowers have investigated testosterone promotion via the steroidogenic pathway in Leydig cell models. This evidence base is entirely pre-clinical.
EU has several pharmacological properties such as antioxidant, anti-inflammatory, antiallergic, antimicrobial, anticancer, antiaging, cardioprotective, and neuroprotective properties. Hence, it has been widely used solely or in combination with other compounds to treat cardiovascular and cerebrovascular diseases, sexual dysfunction, cancer, metabolic syndrome, and neurological diseases. Antioxidant activity includes inhibitory effects against low-density lipoprotein oxidative modification induced by copper, and prevention of oxidative gastric injury. Antioxidant effects of aucubin extracted from E. ulmoides seeds were observed in cardiac dysfunction mouse models. These findings are predominantly from in vitro and animal experiments.
E. ulmoides bark extract, specifically pinoresinol-O-beta-D-glucopyranoside, demonstrated antiviral activity against two strains of H1N1 viruses in vitro. Bioactive compounds from E. ulmoides have been shown to exhibit antimicrobial and antiviral activities in preclinical models. Evidence for these applications is in vitro only.
Dosages vary considerably depending on plant part, form of extract, and indication studied. The following are drawn from peer-reviewed sources:
A 13-week subchronic toxicity study of Eucommia extract was carried out for the first time in a 2020 publication. EUE (Eucommia ulmoides extract) was found to be non-genotoxic and does not result in acute toxicity. The maximum tolerated dose of EUE was not less than 168 g/kg, which is 1,260 times that of clinical doses in human adults.
No acute toxicity in rats occurred with 1,200 mg/kg of E. ulmoides bark extract (standardized to 8% pinoresinol di-beta-D-glucoside); no toxicity was evident as determined by clinical appearance, histopathology, and serum chemistry for repeated dosing of 200, 600, and 1,200 mg/kg over 28 days.
Long-term (13 weeks) administration in animals led to a dose-dependent increase in nephrotoxicity-related indices and pathological changes in renal tissues. These changes were alleviated 5 weeks after ceasing the low dosage of 11.2 g/kg but persisted at the high dosage of 56 g/kg. EUE is non-genotoxic and does not result in acute toxicity; however, long-term and high-dose administration can lead to partly reversible nephrotoxicity. The LOAEL (lowest observed adverse effect level) of Eucommia extract was considered to be 11.2 g/kg/day, which is equal to 84 times the clinical dosage. This finding is from animal studies; its direct applicability to human dosing requires cautious interpretation but signals a need for monitoring in long-term use scenarios.
Eucommia bark and leaves are used as a tea in Japan, and this herb is part of the diet in that area. Eucommia tea has no known toxicity associated with its use. Although Eucommia ulmoides has long been used as medicine or food, systematic toxicity and safety evaluations in humans have been rare.
Eucommia ulmoides extract may interact with certain medications. For example, when combined with antihypertensive drugs, the combined use may cause an excessive drop in blood pressure. It may also interact with medications metabolized by the liver, potentially affecting the efficacy or safety of those medications. These potential interactions are largely theoretical and extrapolated from the plant's known pharmacological profile; direct human pharmacokinetic interaction studies are not yet available for most combinations.
Pregnant and breastfeeding women should avoid using E. ulmoides extract as its safety during pregnancy and lactation has not been fully established. This is particularly notable given the plant's traditional TCM use as a uterine tonic and to prevent miscarriage, which represents a context for which controlled human data are absent.
The leaf and bark of E. ulmoides are officially documented in the Chinese Pharmacopoeia. E. ulmoides has been officially recognized as a medicinal plant and listed in the Chinese Pharmacopoeia. The leaf was officially included in the Chinese Pharmacopoeia in 2005, and in 2023 it was added to China's national "food and medicine dual-use" list. As a dietary supplement in markets such as the United States and European Union, it is not subject to the pre-market approval standards applied to pharmaceutical drugs.
A number of limitations remain in the field: most pharmacological activities have been measured using complex extracts or single isolated compounds in vitro or in vivo with cells or animals. Several challenges persist in the advanced development of Eucommia, including insufficient research on pharmacological mechanisms, limited genetic diversity, and prolonged traditional cultivation cycles. Future research should prioritize elucidating the synergistic mechanisms among different active compounds, advancing technologies for multi-part utilization, and establishing standardized quality evaluation systems.
Extensive in vitro and in vivo data have revealed that E. ulmoides possesses multiple excellent biological activities, including cardiovascular system regulation, anti-osteoporotic, anti-inflammatory, antioxidant, hypolipidemic, neuroprotective, hypoglycemic, anti-obesity, anti-diabetic, hepatoprotective and renal-protective, anti-cancer, immunoregulation, improving erectile function, anti-fatigue, anti-aging, anti-fungal, and anti-bacterial activities, supporting its promising therapeutic application. For the next decade, more clinical indications are expected to be found as more pharmacological mechanisms of E. ulmoides are unveiled.
Health conditions that Eucommia ulmoides may help support.
Eucommia ulmoides (du zhong) bark is a classical Chinese medicine herb specifically indicated for hypertension. Clinical trials in China have demonstrated significant blood pressure-lowering effects. Active compounds include chlorogenic acid, geniposidic acid, and lignans that inhibit the renin-angiotensin system and promote vasodilation.
Eucommia ulmoides (Du Zhong) is a Traditional Chinese Medicine herb used for kidney and bone health, with scientific studies confirming it prevents disuse-induced osteoporosis in animal models. Active compounds including chlorogenic acid, aucubin, and geniposide promote osteoblast activity and inhibit osteoclastogenesis. A peer-reviewed study confirmed Du-zhong prevents disuse-induced osteoporosis in hind limb suspension rats.
Eucommia ulmoides (Du Zhong) bark has been used in Traditional Chinese Medicine for over 2000 years to strengthen bones, tendons, and cartilage. It contains chlorogenic acid, aucubin, and genipin that promote chondrocyte proliferation and inhibit IL-1β–induced MMP expression in vitro. Animal OA models confirm reduced cartilage erosion with Eucommia extract. Human clinical RCT evidence for cartilage endpoints specifically is limited, placing this in the traditional category.
Eucommia ulmoides (Du Zhong) bark is formally listed in the Chinese Pharmacopoeia for strengthening tendons, bones, and the lumbar region—a direct reference to flexibility and mobility support. Modern studies confirm its chlorogenic acid, aucubin, and lignan constituents support collagen synthesis, bone density, and anti-inflammatory properties relevant to joint function.
Body systems that Eucommia ulmoides may help support.
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