Achyranthes japonica

Baekbae (Hundred-fold), the grass that nourishes yet never stops

The 《Shennong Bencao Jing》 gave Achyranthes bidentata (牛膝, Achyranthes japonica) the alias “One name is Baekbae.” As the name suggests, ‘hundred-fold’ can be interpreted as having a hundred times the efficacy, or as nourishing the body with the strong energy of an ox. However, this nickname does not simply refer to a powerful medicinal herb. According to Tao Hongjing's explanation in the 《Jeungryu Bencao》, the name Achyranthes (Useul) was given simply because “its stem has nodes that resemble an ox's knee.” It was also compared to a crane's knee and called ‘Hak-seul,’ and in Korean, it is called ‘Soemureup’ (ox-knee) based on its appearance. While the name is humble, the efficacy recorded in the classics is not. The Bencao lists its effects, including “expelling blood stasis, treating heat-induced inflammation, inducing abortion, treating deficiency of Qi in injuries, supplementing the center to restore exhausted energy, filling the bone marrow, and treating menstrual obstruction and blood stasis in women,” combining nourishing effects with blood circulation and swelling reduction.

It is easy to remember Achyranthes only as a ‘tonic for strengthening the knees and waist.’ This is because its use for heaviness, pain, and weakness in the waist and knees is strongly emphasized. However, the original texts clearly describe characteristics that cannot be explained by ‘supplementing’ alone. The 《Yaksung-ron》 states it “expels stagnant blood and assists the twelve meridians,” the 《Ilhwa-ja》 records it “breaks nodules, discharges pus, relieves pain, and expels dead fetuses,” and the 《Jeonnam Bencao》 notes it “circulates blood, breaks blood stasis and blood clots, and cools blood heat.” In other words, Achyranthes is a medicinal herb that possesses both the power to ‘fill’ and the power to ‘move.’ Jin Sitaek of the 《Bencao Xinbian》 wrote this more directly: “Achyranthes moves and does not stay; it can move blood between interruptions, but it cannot supplement blood within those interruptions.” This means that while Achyranthes continuously moves and circulates blood, it cannot create or fill the blood supply. Therefore, he added, “Achyranthes must be used within a regimen that supplements Qi and blood to achieve the effect of restoring exhausted energy.” Using it solely as a tonic means utilizing only half of its properties.

This ‘non-stopping’ characteristic aligns with the modern perspective of focusing on ‘promoting blood circulation.’ However, this is also why Achyranthes must be used with caution. Classical texts forbade its use during pregnancy, and modern case reports have linked it to interstitial lung disease or acute interstitial nephritis. Because its power to circulate blood and direct energy downward is strong, the dosage, the herbs it is paired with, and the patient's constitution become critical. Those criteria are exactly what this page covers.

Summary at a Glance

The core of Achyranthes is that it possesses both ‘nourishing (補)’ and ‘circulating (通)’ properties. In the table below, you can see its identity, primary uses, and precautions at a glance.

Category	Content
Origin	Hanja Name 牛膝, Scientific Name Achyranthes japonica (Miq.) Nakai. A crude drug made from the dried roots of Achyranthes bidentata native to Korea.
Properties and Meridian Tropism	Bitter and sour taste, neutral property, non-toxic. It primarily acts on the Liver Meridianand Kidney Meridian.
Representative Aliases	Baekbae Shennong Ben Cao Jing; Achyranthes (Useul) Named because the stem nodes are clumped together like a cow's knee.
Efficacy Recorded in Literature	Shennong Ben Cao Jing: Cold-damp atrophy and numbness, contraction of the four limbs, knee pain, promoting blood and qi circulation, wound healing, supplementing the center and restoring severed connections, supplementing the spinal cord, lower back and spinal pain, menstrual obstruction and blood stasis. Yakseongron: Impotence, supplementing the kidneys, supplementing essence, promoting the flow of stagnant blood. Ilhwaja: Cold and weakness of the lower back and knees, breaking down masses, postpartum abdominal pain and fainting due to blood loss, expulsion of dead fetuses.
Main Components and Properties	In modern pharmacological research, Achyranthes japonica there are reports on root extracts, and traditionally it is classified as having properties to tonify the liver and kidneys, strengthen tendons and bones, invigorate blood, and direct energy downwardas its primary tendencies.
Combinations and Contraindications	Combinations: It is used in prescriptions such as Dokhwal Gisaeng-tang, Useul-infused wine, and Useul-tang for the purpose of tonifying the liver and kidneys, strengthening the lower back and knees, and expelling wind-dampness. Contraindicated: Pregnant women (records of miscarriage or stillbirth), menorrhagia (excessive menstrual bleeding), nocturnal emission, spleen-deficiency diarrhea. Combining with beef is avoided in texts such as Yakseongron.

Is this medicinal herb right for me?

Achyranthes bidentata (U-seul) is a medicinal herb that possesses both tonic (supplementing) and promoting (circulating) properties. Therefore, rather than simply viewing it as a 'tonic for deficiency,' it is often more suitable for states where there is deficiency accompanied by stiffness or blockage. However, because its tendency to promote blood circulation and downward movement is distinct, it may worsen symptoms if the individual's constitution and timing are not carefully considered. Please review the following three criteria first.

• Generally suitable cases: Cases where the lower back or knees feel heavy and painful but feel better with movement; cases where standing or walking for long periods is difficult; or cases where it is used under a Korean medicine doctor's prescription during the recovery process after childbirth or surgery. In prescriptions such as Dokhwal-gisaeng-tang from the Cheon-geum-bang, it is used to supplement the liver and kidneys while simultaneously addressing wind-dampness and blood circulation.
• Cases requiring caution: Cases of irregular menstruation or the presence of hard palpable masses in the abdomen; those taking blood pressure medication, anticoagulants, or antiplatelet agents; or those with a history of lung or kidney problems. Since Achyranthes bidentata has blood-circulating and downward-moving effects, the risk of bleeding and potential lung or kidney side effects must be considered.
• Cases to avoid: Those who are pregnant or may be pregnant, those with heavy menstrual bleeding, those with nocturnal emission or spleen-deficiency diarrhea, or situations where beef must be consumed. Yakseongron explicitly states “Avoid beef,” and the Shennong Ben Cao Jing contains records of “miscarriage,” so pregnant women must especially avoid it.

Do not decide whether to take this based on this information alone. Achyranthes bidentata is used in herbal decoctions according to a Korean medicine doctor's prescription; self-administration is not recommended.

Practical Q&A

Achyranthes bidentata is a medicinal herb that is as often misunderstood as its name suggests. While it has a strong image as a 'tonic,' it actually works by both supplementing and circulating, requiring a more meticulous adaptation to the individual's constitution. We have gathered and answered the most common questions from patients considering the use of Achyranthes bidentata.

Is Achyranthes bidentata just a tonic?

No. Achyranthes bidentata is a medicinal herb that possesses both tonic (supplementing) and promoting (circulating) properties. The Shennong Ben Cao Jing states that it “supplements the center, connects the severed, and fills the bone marrow,” while simultaneously recording that it “expels blood-qi and resolves menstrual blockage or blood stasis.” The Boncho Sinpyeon describes it more directly, stating that “Achyranthes bidentata moves and does not stay.” In other words, it has a nature of moving to resolve stiffness that cannot be explained by supplementation alone. Therefore, it is often more suitable for states where there is deficiency accompanied by stiffness or blockage.

Can it be taken during pregnancy?

As a rule, pregnant women should not take it. The original text of the Shennong Ben Cao Jing explicitly mentions “miscarriage,” and records in Yakseongron and Il-hwa-ja mention “dropping a dead fetus.” Modern Chinese medical literature also describes Achyranthes bidentata as a “substance used to break blood stasis, promote menstruation, induce labor, and cause abortion,” viewing it as contraindicated for pregnant women. If you are planning a pregnancy or may be pregnant, you must consult a Korean medicine doctor.

Can I receive a prescription containing Achyranthes bidentata even if I have heavy menstrual bleeding?

Generally, it is not suitable for menorrhagia. Because Achyranthes bidentata has a distinct blood-circulating and downward-moving tendency, it may increase menstrual flow or worsen symptoms in a state where there is already a tendency to bleed. However, as this is an area that a doctor can determine based on the individual's constitution and the overall composition of the prescription, it must be used under the prescription of a Korean medicine doctor.

I usually have knee or back pain; would Achyranthes bidentata be helpful?

Achyranthes bidentata is traditionally used frequently for symptoms related to the “waist and knees.” The Shennong Ben Cao Jing records its primary use for “atrophy and numbness due to cold-dampness, contraction of the four limbs, and knee pain that prevents bending or extending,” and the Il-hwa-ja addresses “weakness, coldness, and fragility of the waist and knees.” However, this is not a simple pain reliever; it is used in prescriptions that consider supplementation, circulation, and wind-dampness according to the constitution and pathogenesis. Examples include Dokhwal-gisaeng-tang, U-seul-tang, and U-seul infused liquor.

Can I boil Achyranthes bidentata as a tea and drink it?

Since medicinal Achyranthes bidentata root is not classified as a general food, self-administration is not recommended. Data from the Korea Institute of Oriental Medicine and the Korea Institute of Drug Evaluation and Management describe a decoction method of putting 5 to 10g of dried root in 0.5L of water, boiling it until it is reduced by half, and taking it 3 times a day between meals. However, because there are clear contraindications such as pregnancy, menorrhagia, nocturnal emission, and spleen-deficiency diarrhea, and cases of lung and kidney side effects have been reported, it is safe to use only under a Korean medicine doctor's prescription and monitoring.

What symptoms should prompt me to visit a hospital while taking this?

If shortness of breath, coughing, or chest pressure occurs, the possibility of interstitial lung disease must be considered. Decreased urine output, hematuria (blood in urine), edema, and fatigue may be signs of acute interstitial nephritis. Additionally, signs of bleeding such as nosebleeds, gum bleeding, skin bruising, and increased menstrual flow require caution regarding the blood-circulating action of Achyranthes bidentata. Severe abdominal pain, diarrhea, and nausea may worsen in those with a spleen-deficient constitution. If these symptoms appear, stop taking it immediately and visit a hospital.

Relationship with Other Medicinal Herbs (Yakdae/Pairing)

Achyranthes bidentata is not used alone. Due to its nature of both supplementing and circulating, it finds its proper role only when paired with other medicinal herbs. In tradition, such pairs are called “Yak-dae” (medicinal pairs); when Achyranthes bidentata is used with tonics, it enhances the supplementing power, and when used with wind-dampness herbs, it enhances the circulating power. Below are representative prescriptions where Achyranthes bidentata forms a core combination.

• Dokhwal-gisaeng-tang A prescription found in the Cheon-geum-bang and the Taiping Huimin Heji Ju Fang. It consists of Dokhwal, Dang-gui, Baek-jak-yak, Sang-gi-saeng, Suk-ji-hwang, Gung-gung, Ginseng, Baek-bok-ryeong, Achyranthes root, Du-jung, Jin-gyo, Se-sin, Bang-pung, Gye-sim, and Gam-cho. It has been traditionally used to supplement the liver and kidneys and resolve dampness in states where wind-cold-dampness invades the liver and kidneys, causing the waist and knees to feel heavy and painful and the legs to lose strength.
• U-seul Infused Liquor (U-seul-jim-ju-bang) A liquor-infusion prescription recorded in the Bo-je-bang and Seong-hye-bang. Achyranthes bidentata, Chim-po, San-jo-in, Gung-gung, Seok-gok, Seon-reung-pi, Jeok-jeon, and Ho-gol were infused in liquor and used for waist and leg pain caused by wind, skin numbness, and tendon contraction.
• U-seul-tang This is a prescription from the 《Seongje Chongnok》, consisting of Achyranthes bidentata (soaked in alcohol, then sliced and dried), dried Magnolia bark, Moutan Cortex, Cyperus rotundus, Polygala tenuifolia, Cinnamon bark, and Osthole. It has been traditionally used for lower back pain caused by wind and pain in the soles of the feet.

When compounding, you must remember the blood-activating and downward-directing properties of Achyranthes bidentata. These prescriptions may also be contraindicated for pregnant women, those with menorrhagia (excessive menstrual bleeding), nocturnal emission, or spleen-deficiency diarrhea. Additionally, the 《Yaksungron》 records “Avoid beef,” so avoiding beef consumption when taking Achyranthes bidentata is a traditional safety guideline.

In what form is it consumed?

Since Achyranthes bidentata is a medicinal herb that both tonifies and clears blockages, the method of consumption varies by purpose. However, not all forms can be used freely. The actual usability of each form is summarized below.

• Tea: This is uncommon. As Achyranthes bidentata is a blood-activating and downward-directing herb with clear contraindications such as pregnancy, menorrhagia, nocturnal emission, and spleen-deficiency diarrhea, it is unsuitable for self-administration in tea form.
• Food: Young shoots can be used as namul (seasoned vegetables), but medicinal roots are not classified as general food. Items such as “Achyranthes bidentata Pork Skin Jelly” introduced by the Korea Institute of Oriental Medicine fall under the category of herbal medicinal cuisine.
• Decoction: This is the most common form. Records indicate a method of putting 5~10g of dried root into 0.5L of water and decocting it until the liquid is reduced by half, then taking it 3 times a day between meals.
• Professional Prescription: In principle, this should be used under the prescription of a doctor of Korean medicine. It is used in traditional prescriptions such as Dokhwal-gisaeng-tang, Achyranthes-infused wine, and Achyranthes decoction for the purposes of tonifying the liver and kidneys, strengthening muscles and bones, and activating blood to reduce swelling; it is combined with other herbs depending on the individual's constitution and symptoms.

Overall, the root of Achyranthes bidentata is a medicinal herb that requires decoction and for which self-administration is not recommended. It is safer for pregnant women, those with menorrhagia, a constitution of spleen-deficiency or nocturnal emission, or a tendency toward bleeding to decide whether to use it after consulting a doctor of Korean medicine.

Interactions and Safety During Use

As Achyranthes bidentata is a medicinal herb that exhibits both tonifying and clearing properties, its precautions are as clear as its efficacy. In particular, its blood-activating and downward-directing tendencies are distinct, and incorrect use may worsen symptoms, so it is important to accurately consider the individual's constitution and the timing of use.

• Pregnant women must not take this. The original text of the 《Shennong Bencao Jing》 specifies “abortion (墮胎),” and the 《Yaksungron》 and 《Ilhwaja》 also record “expelling a dead fetus (落死胎).” In modern Chinese medical literature, Achyranthes bidentata is known to be contraindicated for pregnant women due to its tendency to “break blood, clear menstruation, and induce labor or abortion.”
• Avoid use in cases of heavy menstrual bleeding. Its blood-activating and downward-directing actions may increase menstrual flow.
• Caution is required for those with a constitution prone to nocturnal emission or spleen-deficiency diarrhea. Because its properties are downward-directing and slippery (滑竅), it may be unsuitable for individuals with these tendencies.
• Avoid taking this with beef. The 《Yaksungron》 records “Avoid beef (忌牛肉),” and the contraindication for beef is also passed down in texts such as the 《Imwon Gyeongjeji》.
• Cases of adverse reactions related to the lungs and kidneys have been reported. Achyranthes japonica Following the consumption of the root, 3 cases of interstitial lung disease and 1 case of acute interstitial nephritis have been reported as case reports. When taking it for a long period, it is necessary to monitor respiratory and kidney function.
• Be mindful of the risk of bleeding when using in combination with Western medicines. Specific interactions with warfarin, anticoagulants, or antiplatelet agents have not been directly confirmed in official or academic sources; however, considering the blood-activating and downward-directing effects of Achyranthes root (Useul), caution is required when used concurrently with Western medicines that increase the risk of bleeding.

If any of the following symptoms appear, stop taking the medicine and visit a hospital immediately.

• Cough, shortness of breath, chest tightness, hypoxia
• Decreased urine output, hematuria (blood in urine), edema, fatigue
• Epistaxis (nosebleeds), gum bleeding, skin bruising, increased menstrual flow
• Severe abdominal pain, diarrhea, nausea

In principle, Achyranthes root should be used in the form of a decoction under the prescription of a Korean medicine doctor. Please consult a professional to determine if you have contraindications such as pregnancy, menorrhagia (excessive menstruation), nocturnal emission, or spleen-deficiency diarrhea, and to check for interactions with any Western medicines you are currently taking. Please inquire during your consultation regarding the specific dosage and duration.

If you experience these symptoms

If you experience these symptoms

Since Achyranthes root possesses both tonic (supplementing) and promoting (circulating) properties, you must stop taking it immediately and notify your attending Korean medicine doctor if the following signals appear. In particular, cases affecting the lungs and kidneys have been reported in modern literature, requiring greater caution during long-term use. It is safer to receive a professional evaluation rather than reducing the dose or switching to other herbs on your own.

• Respiratory Symptoms: If cough, shortness of breath, chest tightness, or hypoxia occur, the possibility of interstitial lung disease must be considered.
• Kidney-related Symptoms: If decreased urine output, hematuria, edema, or persistent fatigue occur, acute interstitial nephritis should be suspected.
• Signs of Bleeding: Symptoms such as nosebleeds, gum bleeding, skin bruising, or increased menstrual flow may be related to the blood-activating effect of Achyranthes root.
• Digestive Symptoms: If severe abdominal pain, diarrhea, or nausea occur, symptoms may have worsened in those with a spleen-deficiency (Bi-heo) constitution.
• General Deterioration of Condition: If accompanied by fever, general weakness, or weight loss, the connection to the medication must be verified.

If symptoms are severe or progress rapidly, it is appropriate to visit an emergency medical institution.

Differences from other restorative medicines

Achyranthes root falls under the category of tonic medicine, but it differs in nature from tonics that only supplement. As recorded in the "Shennong Ben Cao Jing" regarding both "supplementing the center and connecting the severed" and "expelling blood and qi," it possesses both the power to supplement and the power to circulate; therefore, it is insufficient to understand it simply as a medicine that "fills empty areas." Consequently, its use differs from typical restorative tonics such as Gongjin-dan or Gyeongok-go.

Gongjin-dan focuses on supplementing the qi and blood of the five viscera and six entrails and stabilizing the mind, while Gyeongok-go is a prescription commonly used to supplement blood deficiency and senescence in women. These primarily focus on the supplementing direction. In contrast, Achyranthes root has a distinct tendency to supplement the liver and kidneys, strengthen the muscles and bones, and activate blood and direct it downward; thus, it is more frequently considered when deficiency symptoms coexist with blocked meridians or sluggish blood flow. A representative example is Dokhwal-gisaeng-tang, which is structured to supplement the liver and kidneys while resolving wind-cold-dampness pathogens and blood flow disorders, with Achyranthes root serving as the link between supplementing and circulating.

However, there is insufficient official or academic evidence to state uniformly which tonics Achyranthes root can be used with or which constitutions it may not suit. In particular, those with nocturnal emission, spleen-deficiency diarrhea, excessive menstrual flow, or those who are pregnant may be at risk if they take it simply because it is called a tonic. It is recommended to confirm through a consultation whether Achyranthes root is a suitable tonic for your constitution and symptoms, or if another prescription is more appropriate.

References

1. Evidence material related to Achyranthes root 1: Supporting data from data.go.kr.
2. Evidence material related to Achyranthes root 2: Korea Institute of Korean Medicine official data.
3. Evidence material related to Achyranthes root 3: Crude drug data from the National Institute of Food and Drug Safety Evaluation.
4. Supporting evidence for Achyranthes japonica 4: GBIF plant classification data.
5. Supporting evidence for Achyranthes japonica 5: GBIF plant classification data.
6. Supporting evidence for Achyranthes japonica 6: Korea Citation Index academic paper.
7. Supporting evidence for Achyranthes japonica 7: Korea Citation Index academic paper.
8. Supporting evidence for Achyranthes japonica 8: Korea Citation Index academic paper.

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