Roots and rhizomesBlood-activatingRhizoma Corydalis

Yan Hu Suo (Corydalis Rhizome)

A practical guide to Yan Hu Suo: what it is, how Traditional Chinese Medicine uses it, the classical formulas it appears in, and who should be careful with it.

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Last reviewed Oct 13, 2026

Quick Facts

Latin NameRhizoma Corydalis
Chinese Name & Pinyin 延胡索 · Yan Hu Suo
Medicinal PartRoots and rhizomes
The herbYan Hu Suo is the dried tuber of Corydalis yanhusuo. The cut face is yellow. Common forms: raw and vinegar-fried. It is not an opioid drug.
Nature and channelsAcrid, bitter, warm. Enters the Liver and Spleen. Acridity moves qi and blood. Bitterness drains stagnation. Warmth unblocks.
Pharmacopoeia lineInvigorates blood. Moves qi. Relieves pain. Used for pain in the chest, flanks, or abdomen, amenorrhea and dysmenorrhea, postpartum stasis, and trauma swelling and pain.
Pattern cuesDistending or stabbing pain. Clotted painful periods. Postpartum abdominal pain. Traumatic bruising. Dark tongue.
In this articleYan Hu Suo versus Chuan Xiong, Mo Yao, and Chuan Lian Zi. Raw versus vinegar-fried. Why pregnancy is a stop sign. Who should skip it.

What Is Yan Hu Suo?

Yan Hu Suo (延胡索; Yán Hú Suǒ; Latin: Corydalis Rhizoma; English: corydalis rhizome) is the dried tuber of Corydalis yanhusuo W. T. Wang. In Chinese medicine it is a blood-invigorating herb. It is acrid, bitter, and warm, enters the Liver and Spleen channels, and its core actions are to invigorate blood, move qi, and relieve pain. Tradition says it moves qi stagnation inside the blood and blood stagnation inside the qi, so pain above and below can be considered—after pattern diagnosis. It is not opium. It is not a Western analgesic to raise on your own. Vinegar-fried Yan Hu Suo enters the Liver more cleanly and stops pain more clearly. It is not Chuan Xiong. Chuan Xiong rises and reaches the head and eyes. Yan Hu Suo is more specific for moving blood and qi to stop pain. It is not Mo Yao, which leans toward dispelling stasis, reducing swelling, and generating flesh. Avoid in pregnancy.

It is used most often for three patterns:

  • Qi and blood stasis pain — stabbing or distending pain in the chest, flanks, or abdomen
  • Painful periods and postpartum stasis
  • Traumatic swelling and pain

The usual decoction dose is 3–10 g. Blood deficiency without stasis is a caution. Acrid, bitter, warm, and unblocking, it is not a daily “universal pain tuber.” Pain that is getting worse, or an acute abdomen, needs a clinic first.

When qi stagnation and blood stasis cause pain, clotted cramps and flank distention are common. Yan Hu Suo is acrid-dispersing and bitter-draining. It moves and stops pain, which is why it is paired with Chuan Lian Zi in Jin Ling Zi San. It moves more than it holds. A pale face, scant flow, and dull pain with no stasis become weaker if more movement is added.

Yan Hu Suo is not a catch-all pain herb. Moving when there is no stasis, or use in pregnancy, can consume and stir blood. Raw or vinegar-fried should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Yan Hu Suo Corydalis Rhizome

Yan Hu Suo: Materia Medica Profile

Identification & Quality Standard

Rhizoma Corydalis

Botanical Origin

The dried tuberous rhizome of Corydalis yanhusuo W. T.Wang. (Papaceraceae)

Production Regions

Primarily produced in the Chinese province of Zhejiang.

Quality Requirements

Superior medicinal material is large, full, firm, yellow, and shiny yellow inside.

Macroscopic Features

Irregular flat spherical shape, 1~2cm diameter, externally yellow or brownish-yellow, apex center has slightly indented stem scar, base has knotted protrusions. Hard and brittle texture, yellow fractured surface horn-like, with wax-like luster. faint odor, bitter taste.

Authentic Regions and Quality Identification

Historically, the Zhejiang province is highly regarded for producing top-quality Yan Hu Suo (Corydalis Rhizome).

  • Visual Quality: A good quality tuber is a small, irregular flat sphere (about 0.5 to 1.5 cm wide) with a yellow or yellow-brown surface and a hard, waxy interior.
  • Taste and Smell: It has a slightly bitter taste. The vinegar-processed version is darker with a distinct vinegar aroma, while the wine-processed one smells faintly of alcohol.
  • Identification: It is sometimes confused with a similar plant tuber called Xia Tian Wu, but that look-alike has a whiter interior and a much milder scent.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Acrid, Bitter; WarmHeartLiverSpleen

1. Historical Records

This herb has been trusted for centuries to manage pain:

  • Lei Gong Pao Zhi Lun first noted its ability to treat severe, agonizing chest pain.
  • Ming Yi Bie Lu highlighted its use in women’s health, specifically for breaking up blood stasis, regulating irregular periods, and easing postpartum abdominal pain.
  • Ben Cao Gang Mu summarized its core traditional benefits perfectly: it invigorates blood, regulates Qi, and stops pain.

2. Evolution of TCM Understanding

Over the centuries, how doctors used this herb evolved. Early practitioners relied on it heavily for severe blood stasis (like intense postpartum pain or internal masses). Later, doctors realized it was also excellent at smoothing out "Liver Qi"—making it a go-to for stress-induced stomach aches or rib pain. Because of its neutral nature, it became incredibly popular; it can treat various types of pain without causing the extreme heat or cold side effects that other pain-relieving herbs might trigger.

Yan Hu Suo Corydalis Rhizome

Core Efficacies & Traditional Applications

Traditional Functions

Invigorates blood, disperses stasis, moves qi, stops pain. Apply to chest impediment and heart pain, flank and abdomen pain, headache, waist pain, hernis pain, sinew and bone pain, dysmenorrhea, amenorrhea, postpartum blood stasis and abdominal pain, injury from falls.

1. Primary Focus: Regulating Qi to Relieve Pain

  • Traditional Function: Yan Hu Suo (Corydalis Rhizome) is famous for smoothing the flow of Qi (vital energy) to relieve pain. It is highly effective for pain caused by Qi stagnation.
  • Target Symptoms: It targets distending (bloating) pain in the ribs, stomach aches, and hernia pain, especially when these are linked to emotional stress or a stagnant Liver Qi. For example, rib pain that worsens when you are in a bad mood, or stomach bloating that improves slightly after burping.
  • Common Pairings: It is often combined with Qi-regulating herbs like Chai Hu (Bupleurum Root) or Xiang Fu (Cyperus Rhizome) for Liver Qi issues, or with Mu Xiang (Aucklandia Root) and Sha Ren (Cardamom Seed) for digestive discomfort.
  • When to Avoid: Do not use this herb if your pain is caused by Qi deficiency (characterized by a dull, lingering ache accompanied by fatigue and shortness of breath), as its "moving" nature can deplete your energy further.

2. Secondary Focus: Invigorating Blood to Relieve Pain

  • Traditional Function: Beyond moving Qi, it breaks up blood stasis to stop pain.
  • Target Symptoms: It is great for stabbing, localized pain that worsens at night or with cold. Common uses include painful menstruation (dysmenorrhea) with clots, trauma from falls or injuries, and chest pain.
  • Common Pairings: Often paired with blood-moving herbs like Dang Gui (Angelica Root) and Chuan Xiong (Szechuan Lovage Root), or with Ru Xiang (Frankincense) and Mo Yao (Myrrh) for enhanced pain relief.
  • When to Avoid: Pregnant women must avoid it due to its strong blood-invigorating effects. Women with heavy menstrual bleeding should also avoid using it during their period.

3. Common Herb Pairings: Synergistic Duos

  • A classic combination is Yan Hu Suo (Corydalis Rhizome) paired with Xiang Fu (Cyperus Rhizome).
  • Why it works: Yan Hu Suo (Corydalis Rhizome) excels at moving blood to stop pain, while Xiang Fu (Cyperus Rhizome) is a master at regulating Liver Qi and relieving emotional depression. Together, they regulate both Qi and blood, making this duo perfect for menstrual cramps or rib pain triggered by stress. Always use under the guidance of a TCM practitioner.

Yan Hu Suo Corydalis Rhizome

Modern Research

Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.

1. Main Chemical Components

Modern science has identified alkaloids (such as tetrahydropalmatine, or THP) as the primary active compounds in the plant.

  • Lab Observations: In test-tube studies, some of these compounds can relax smooth muscles. In animal models, extracts have shown potential to reduce pain responses. However, these small-scale lab results cannot be directly equated to how the herb works in the human body.

2. Modern Pharmacological Focus

Current research mostly focuses on how these alkaloids provide pain relief and interact with the central nervous system. Interestingly, modern lab tests confirm that boiling the herb with vinegar (the traditional TCM processing method) significantly increases the release of its alkaloids, validating centuries-old herbal practices.

3. Limitations of Modern Research

While the science is interesting, it has limits:

  • Lab vs. Real World: Animal and test-tube studies do not perfectly mirror human digestion and metabolism.
  • Extracts vs. Whole Herb: Scientists often test highly concentrated, isolated chemicals (like pure THP). In contrast, traditional use involves brewing the whole Yan Hu Suo (Corydalis Rhizome) root, which is much gentler.
  • Holistic Action: TCM relies on the synergy of all the natural compounds within the plant working together, not just one isolated molecule. Therefore, isolating one active ingredient doesn't capture the full traditional effect of the herb.

Yan Hu Suo Corydalis Rhizome

Comparing Similar Herbs

1. Shared Traits with Similar Herbs

Yan Hu Suo (Corydalis Rhizome) is often compared to Chuan Xiong (Szechuan Lovage Root):

  • Both invigorate blood and relieve pain.
  • Both treat pain caused by Qi and blood stagnation.
  • Both are heavily used in gynecology for menstrual pain and postpartum recovery.

2. Core Differences

  • Nature and Temperature: Yan Hu Suo (Corydalis Rhizome) is neutral (neither hot nor cold), making it suitable for many body types. Chuan Xiong (Szechuan Lovage Root) is warm, which can aggravate internal heat.
  • Core Strength: Yan Hu Suo (Corydalis Rhizome) focuses more on regulating Qi to treat distending pain (like a bloated stomach or tight ribs). Chuan Xiong (Szechuan Lovage Root) focuses heavily on moving blood to treat stabbing pain.
  • Direction of Action: Yan Hu Suo (Corydalis Rhizome) directs energy downward, clearing stagnation in the liver and digestive system. Chuan Xiong (Szechuan Lovage Root) moves upward and outward, making it especially famous for treating headaches.

3. A One-Sentence Summary

Yan Hu Suo (Corydalis Rhizome) is your neutral go-to for distending pain caused by Qi stagnation, while Chuan Xiong (Szechuan Lovage Root) is a warming herb better suited for stabbing pain and headaches caused by blood stasis.

Yan Hu Suo Corydalis Rhizome

Classical Formulas Containing Yan Hu Suo

Formulas vs. Single Herbs

  • Synergy is Key: A formula is a balanced team. The healing power comes from how the herbs interact, so a single herb cannot simply replicate a full formula's effects.
  • Holistic Balance: The exact dosage and combination in a formula affect the entire body. Never try to mix or alter these formulas at home based on internet articles.

Diet & Daily Home Use

1. Home Herbal Teas

  • Yan Hu Suo and Xiang Fu Tea:
    • Ingredients: 3g Yan Hu Suo (Corydalis Rhizome), 5g Xiang Fu (Cyperus Rhizome), 2g Chen Pi (Tangerine Peel).
    • Method: Rinse the herbs, place in a teapot, and steep with boiling water for 10 minutes.
    • Best For: Mild rib tightness or stomach discomfort caused by stress or a bad mood.
    • Avoid If: You are pregnant, have heavy periods, or suffer from internal heat (frequent mouth ulcers, dry mouth).
    • Frequency: Drink 2-3 times a week. Do not use continuously for long periods.

2. Preparation Differences

  • Raw vs. Vinegar-Processed: Raw Yan Hu Suo (Corydalis Rhizome) is better for moving blood stasis. The vinegar-processed version is significantly stronger at stopping pain and regulating Qi, as the vinegar helps draw out the active alkaloids.
  • Brewing: It does not require special cooking methods. Simply soak it with other herbs for 30 minutes before boiling. Remember, you cannot swap raw herb dosages with concentrated powder dosages.

3. Dosage and Usage Cycles

  • Dosage: Clinical doses range from 3–10g. For home wellness teas, keep the dosage small (around 3g).
  • Duration: Do not take this herb long-term. Use it for a maximum of 1 week to manage symptoms; if the pain persists, consult a doctor.
Yan Hu Suo Corydalis Rhizome

Contraindications & Safety Warnings

1. Who Should Avoid It

  • Qi Deficiency / Yin Deficiency: Avoid if your pain is accompanied by extreme fatigue, or if you have severe dry mouth and a red tongue.
  • Vulnerable Populations: Pregnant and nursing women must avoid it. Children and the elderly should only use it under strict medical supervision.
  • Organ Health: Avoid self-prescribing if you have liver or kidney impairment, or if you are allergic to plants in the poppy family.

2. Medication Interactions and Dietary Notes

  • Drug Interactions: Yan Hu Suo (Corydalis Rhizome) can interact with blood thinners (like Warfarin), increasing the risk of bleeding. It may also enhance the effects of sedatives, causing excessive drowsiness. Always consult your doctor if you are on blood pressure or diabetes medication.
  • Separate herbal teas and Western medications by at least 1-2 hours.

3. Adverse Reactions and Overdose

  • Mild Side Effects: Improper dosing may cause nausea, dizziness, or stomach upset.
  • Overdose Risks: Because it affects the central nervous system, taking too much can cause severe drowsiness or respiratory depression.
  • When to Stop: If you experience rashes, persistent vomiting, breathing difficulties, or extreme dizziness, stop taking it immediately and seek emergency medical care.

Frequently Asked Questions About Yan Hu Suo

What is Yan Hu Suo? Are Yuan Hu, Cu Yan Hu Suo and Chuan Xiong the same?
Official Yan Hu Suo (延胡索) is the dried tuber of Corydalis yanhusuo, also called Yuan Hu. The pharmacopoeial name is Corydalis Rhizoma. Cu Yan Hu Suo is vinegar-fried or vinegar-boiled to strengthen invigorating Blood and stopping pain—the form most prescriptions expect. Chuan Xiong is acrid-warm: invigorates Blood, moves qi and dispels wind to stop pain—the qi herb within Blood, leaning toward headache and regulating menses, not Corydalis. Classics say it moves qi stagnation within Blood and Blood stasis within qi, and is specific for pain. Write Yan Hu Suo, Yuan Hu or Cu Yan Hu Suo; crush or slice before use.
What are the TCM properties and traditional uses of Yan Hu Suo?
According to the Chinese Pharmacopoeia, Yan Hu Suo is acrid, bitter and warm, enters the Liver and Spleen channels (also often the Heart), and acts to invigorate Blood, move qi and stop pain. It is used for chest-flank and epigastric-abdominal pain, chest impediment Heart pain, amenorrhea and dysmenorrhea, postpartum static obstruction and traumatic swelling pain. Acrid-bitter and warm-unblocking, it regulates both qi and Blood—suited to pain from qi stagnation and Blood stasis, not to reckless Blood heat, qi-Blood vacuity without stasis, or pregnancy.
How do you choose raw versus vinegar-processed? How do powder and decoction differ?
Stopping pain usually prefers Cu Yan Hu Suo. Decoction is 3–10 g, crushed; swallowed powder is only 1.5–3 g each time and more concentrated. Do not raise the powder dose on your own. Dongyang and Pan’an, Zhejiang lots are preferred.
What is the usual dosage? Can it be drunk daily as an all-purpose pain tea?
The pharmacopoeial decoction dose is 3–10 g; powder 1.5–3 g each time. It is not a four-season “Yuan Hu pain tea.” Blood heat and qi vacuity without stasis only empty further. Chest-flank and epigastric pain and dysmenorrhea need a practitioner to name vinegar processing and a short course.
What are the contraindications? Can it be used in pregnancy?
Forbid in pregnancy. Use caution or forbid in reckless Blood heat, early menses, and qi-Blood vacuity without stasis. Use caution in bodily vacuity. Stop if dizziness or drowsiness appears; do not drive until the reaction is clear. Acute abdomen and radiating chest pain are emergencies—do not let analgesia mask them.
Can Yan Hu Suo invigorate Blood, move qi and stop pain?
It can help pain from qi stagnation and Blood stasis. Liver depression transforming into heat with Heart-abdominal and flank pain joins Toosendan in Jin Ling Zi San. Chest impediment may join Salvia and chuanxiong. Dysmenorrhea joins angelica, Cyperus and chuanxiong. Trauma joins frankincense and myrrh. It regulates qi and Blood together to stop pain—not a specific for every pain, every dysmenorrhea or every angina. Myocardial infarction and acute abdomen are emergencies.
Can Yan Hu Suo be drunk daily as a pain, sleep or dysmenorrhea tea?
Qi-stagnation Blood-stasis stabbing pain may enter a short formula; Blood-qi vacuity without stasis only empties further. “Yuan Hu stops all pain and aids sleep” does not replace etiologic assessment of pain. Invigorating Blood, moving qi and stopping pain should name Cu Yan Hu Suo 3–10 g; pregnancy forbids it.
How do you choose among Yan Hu Suo, Chuan Xiong, Xiang Fu, Wu Ling Zhi and Chuan Lian Zi?
Corydalis is acrid-bitter-warm: invigorates Blood, moves qi and stops pain—Liver-Spleen, regulates qi and Blood together, broad for pain. Chuanxiong is acrid-warm: invigorates Blood, moves qi and dispels wind to stop pain—the qi herb within Blood, head-body and menses. Cyperus is acrid, slightly bitter, slightly sweet and neutral: soothes the Liver, regulates qi and regulates menses to stop pain—commander of qi diseases. Trogopterus feces is bitter-sweet-warm: invigorates Blood, stops pain and transforms stasis to stop bleeding—static pain specifically; antagonizes ginseng; wrap for decoction. Toosendan is bitter-cold and slightly toxic: soothes the Liver, drains heat, moves qi, stops pain and kills parasites—Liver depression transforming into heat. Pain in general favors Yan Hu Suo; headache and regulating menses favor Chuan Xiong; Liver depression and menses favor Xiang Fu; stabbing pain with clots favors Wu Ling Zhi; heat pain favors Chuan Lian Zi with Yan Hu Suo (Jin Ling Zi San). They may be paired; pregnancy and vacuity without stasis forbid pure breaking and moving.
Which herbs is Yan Hu Suo combined with? What are the representative formulas?
Liver-depression heat pain joins Toosendan in Jin Ling Zi San. Dysmenorrhea joins angelica, chuanxiong, Cyperus and white peony. Chest impediment joins Salvia and Allium macrostemon. Trauma joins frankincense and myrrh. Write Cu Yan Hu Suo; crush 3–10 g in decoction; do not use in pregnancy.
How do you choose and store Yan Hu Suo?
Choose flattened-spherical yellow or yellow-brown tubers with a bright yellow horny fracture and a bitter taste; Zhejiang lots are preferred. Hollow, moldy, moth-eaten and pale fractures are inferior. Store dry against moths. Buy pharmacopoeial Yan Hu Suo or Cu Yan Hu Suo; do not replace invigorating Blood, moving qi and stopping pain with an unidentified poppy-family tuber by equal weight.

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Medical Disclaimer — This article is provided for educational purposes only and describes traditional Chinese medicine concepts. It is not medical advice, and it is not intended to diagnose, treat, cure or prevent any disease. Always consult a qualified practitioner before using any herb, particularly if you are pregnant, nursing, taking medication or managing a diagnosed condition.

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Yan Hu Suo (Corydalis Rhizome): Invigorate Blood, Move Qi, and Stop Pain