Xia Ku Cao (夏枯草): Prunella in TCM — The Herb That Clears Liver Fire and Dissolves Nodules
Discover Xia Ku Cao (Prunella vulgaris / Self-Heal), the TCM herb that clears Liver fire, dissolves nodules, reduces eye pressure, and treats headaches, swollen lymph nodes, and hyperthyroidism patterns.
What Is Xia Ku Cao?
Xia Ku Cao (夏枯草), meaning “Summer-Withered Grass,” is the dried fruiting spike of Prunella vulgaris, commonly known as Self-Heal. This humble plant grows in meadows and fields worldwide, but has been a valued medicinal herb in TCM for over 2,000 years.
Its name comes from the plant’s unusual life cycle: it grows vigorously in spring, produces purple flower spikes, then the above-ground portion withers when summer arrives — as if the summer heat has defeated it. In TCM, this behavior is seen as evidence of the plant’s cooling nature.
Xia Ku Cao occupies a unique position in the TCM pharmacy: it is both a heat-clearing herb and a nodule-dissolving herb, making it the herb of choice for conditions where heat has congealed fluids into hard lumps.
Basic Information
| Property | Details |
|---|---|
| Chinese name | 夏枯草 (Xià Kū Cǎo) |
| English name | Prunella, Self-Heal |
| Pharmaceutical name | Prunellae Spica |
| Source | Dried fruiting spikes of Prunella vulgaris |
| Nature | Cold |
| Flavor | Bitter, pungent |
| Meridian affinity | Liver, Gallbladder |
| Dosage | 10–15g (decoction) |
TCM Properties and Actions
Primary Actions
- Clears Liver fire (清肝火) — the primary heat-clearing action
- Dispels nodules and reduces swelling (散结消肿) — its distinguishing property
- Brightens the eyes (明目) — through clearing Liver fire
Why Xia Ku Cao Is Special
Most heat-clearing herbs either clear heat or dissolve nodules — rarely both. Xia Ku Cao does both simultaneously, making it essential for:
- Swollen lymph nodes with heat signs
- Thyroid nodules and goiter
- Breast lumps from Liver fire and Phlegm
- Eye inflammation with headache
Clinical Applications
1. Red, Swollen, Painful Eyes (目赤肿痛)
When Liver fire rises to the eyes:
- Red, bloodshot eyes with pain
- Sensitivity to light
- Eye pressure and headache behind the eyes
- Often combined with Ju Hua, Jue Ming Zi
2. Headaches from Liver Fire (肝火头痛)
- Unilateral headache, especially at temples or sides
- Throbbing pain
- Red face and bloodshot eyes
- Irritability
- Worse with stress or anger
3. Swollen Lymph Nodes and Scrofula (瘰疬痰核)
This is Xia Ku Cao’s signature application:
- Enlarged cervical lymph nodes
- Hard, palpable nodules under the skin
- Scrofula (tuberculosis of lymph nodes)
- Often combined with Zhe Bei Mu (Fritillaria), Xuan Shen
4. Thyroid Conditions (瘿瘤)
- Thyroid nodules
- Simple goiter
- Hyperthyroidism with Liver fire signs
- Often combined with Zhe Bei Mu, Hai Zao (Seaweed), Mu Li (Oyster Shell)
5. Hypertension (高血压)
Modern TCM frequently uses Xia Ku Cao for:
- High blood pressure with Liver fire pattern
- Headache and dizziness with flushed face
- Often combined with Tian Ma, Gou Teng, Shi Jue Ming
6. Breast Lumps (乳癖)
- Fibrocystic breast changes
- Breast lumps from Liver Qi stagnation + Phlegm
- Tender before menstruation
- Often combined with Chai Hu, Zhe Bei Mu, Ru Xiang
Classic Formulas
Xia Ku Cao Tang (夏枯草汤)
A simple formula focused on the herb’s core functions:
- Xia Ku Cao + Xiang Fu + Gan Cao
- For scrofula, nodules, and Liver fire conditions
Clinical Combinations
| Combination | Purpose |
|---|---|
| Xia Ku Cao + Ju Hua + Jue Ming Zi | Severe eye inflammation from Liver fire |
| Xia Ku Cao + Zhe Bei Mu + Xuan Shen | Swollen lymph nodes, thyroid nodules |
| Xia Ku Cao + Tian Ma + Gou Teng | Hypertension with headache |
| Xia Ku Cao + Chai Hu + Bai Shao | Breast lumps from Liver Qi stagnation |
| Xia Ku Cao + Hai Zao + Mu Li | Thyroid goiter and nodules |
Xia Ku Cao vs. Other Heat-Clearing Herbs
| Feature | Xia Ku Cao | Long Dan Cao | Jue Ming Zi |
|---|---|---|---|
| Strength | Moderate fire-clearing | Strongest Liver fire herb | Mild fire-clearing |
| Nodule-dissolving | Yes — unique strength | No | No |
| Best for | Nodules + Liver fire | Severe acute Liver fire | Eyes + constipation |
| Tolerance | Well-tolerated | Harsh — can damage digestion | Gentle |
| Everyday use | Yes, as tea | No — too harsh | Yes, as tea |
Preparation and Usage
Xia Ku Cao Tea (夏枯草茶)
- Take 10–15g dried Xia Ku Cao
- Rinse briefly
- Simmer in 2 cups water for 10–15 minutes
- Add honey or rock sugar if desired
- Drink 1–2 cups daily
Often combined with Ju Hua and Bing Tang (rock sugar) for a pleasant cooling tea popular in southern China during summer.
In Decoction
- Standard dose: 10–15g
- Can be cooked with other herbs normally
- For eye conditions, can be used as a warm compress after brewing
Modern Research
Contemporary studies on Xia Ku Cao have found:
- Antihypertensive — helps lower blood pressure through vasodilation
- Antitumor — shows activity against various cancer cell lines in vitro
- Anti-inflammatory — reduces inflammatory markers
- Immunomodulatory — modulates immune cell activity
- Antiviral — activity against herpes simplex and HIV in laboratory studies
- Antioxidant — phenolic compounds provide free radical scavenging
- Thyroid-regulating — may help regulate thyroid function
Key active compounds: ursolic acid, rosmarinic acid, prunellin, oleanolic acid.
Precautions
| Situation | Guidance |
|---|---|
| Spleen-Stomach cold deficiency | Use cautiously — cold nature may worsen diarrhea |
| Pregnancy | Avoid — promotes movement and dissolving |
| Qi deficiency without fire | Not suitable — this is a heat-clearing, not tonifying herb |
| Long-term use | Monitor for cold patterns developing |
Key Takeaways
- Xia Ku Cao (Prunella) uniquely combines Liver fire-clearing with nodule-dissolving action
- The premier herb for swollen lymph nodes, thyroid nodules, and breast lumps with heat
- Also effective for red eyes, temple headaches, and hypertension from Liver fire
- Well-tolerated and can be used as a daily tea during summer
- Modern research supports antihypertensive, anti-inflammatory, and antitumor properties
- Name “Summer-Withered Grass” reflects the plant’s heat-sensitive nature
Disclaimer: This article is for educational purposes only. Consult a licensed TCM practitioner before using Xia Ku Cao or any herbal preparation.
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FAQ
What is Xia Ku Cao used for in TCM?
Xia Ku Cao (夏枯草, Prunella vulgaris / Self-Heal) is primarily used to clear Liver fire, disperse nodules, and improve vision. Its name means 'summer-withered grass' because the plant withers when summer arrives. Clinically, it treats red swollen painful eyes, headaches at the temples and sides of the head, swollen lymph nodes (scrofula), thyroid nodules, breast lumps, and hypertension with Liver fire signs. It is considered one of the best herbs for conditions involving both heat and nodules or lumps.
Why is it called 'Summer-Withered Grass'?
The name 夏枯草 (Xià Kū Cǎo) literally means 'summer-withered grass.' The Prunella vulgaris plant grows in spring and produces flower spikes, but the entire above-ground portion withers and dies when summer heat arrives — hence the name. In TCM philosophy, this botanical behavior is significant: the plant's nature of yielding to summer heat mirrors its medicinal property of clearing heat. The dried flower spikes are harvested just before they wither, typically in late spring to early summer.
Disclaimer
This content is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before using any herbal preparation.