Xia Ku Cao (夏枯草) — Prunella Spike: TCM Uses, Formulas & Benefits

At a Glance

Herb: Xia Ku Cao
Chinese name: 夏枯草 (Xià Kū Cǎo)
Latin name: Prunella vulgaris L.
Nature: Cold
Taste: Bitter / Acrid
Meridian: Liver / Gallbladder
Category: Herbs that Clear Heat and Purge Fire
Introduction: Xia Ku Cao (夏枯草), the dried spikes of Prunella vulgaris L., derives its Chinese name — ‘summer withering grass’ — from its habit of drying up in summer, reflecting its function of draining the fire that peaks during the summer season. First recorded in the Shen Nong Ben Cao Jing, it is the primary herb for clearing liver fire affecting the eyes and head, and for resolving phlegm-fire accumulations such as scrofula and thyroid nodules. Modern research has identified rosmarinic acid, ursolic acid, oleanolic acid, and polysaccharides with documented anti-hypertensive, anti-thyroid, antibacterial, and antitumor activities.

Clears liver fire — treats red, painful, swollen eyes and headache from liver fire
Brightens the eyes — relieves photophobia, tearing, and dim vision from liver-kidney deficiency or fire
Resolves phlegm and dissipates nodules — treats scrofula, goiter, and thyroid masses
Lowers blood pressure — used in modern practice for hypertension from liver yang rising

Liver fire blazing upward: red, painful, swollen eyes, headache, dizziness — combined with Jue Ming Zi, Ju Hua
Eye conditions: photophobia, excessive tearing, cataracts from liver-kidney deficiency
Scrofula (luó lì) from phlegm-fire: neck lymph node swellings — combined with Zhe Bei Mu, Xuan Shen, Mu Li
Goiter and thyroid nodules from qi-phlegm stagnation
Hypertension with liver yang rising: headache, dizziness, flushed face

Standard dose: 9–15 g; up to 30 g in some preparations
Use with caution in spleen-stomach deficiency — its cold, bitter nature may injure the middl e jiao
Contraindicated in cases of deficiency without fire
May interact with thyroid medications — use caution in patients on thyroid hormone replacement
Long-term use without monitoring is not recommended in cases of weak digestion

Xia Ku Cao Gao (夏枯草膏): Xia Ku Cao alone, decocted to a thick syrup — classic preparation for scrofula
Xia Ku Cao San (夏枯草散): Xia Ku Cao, Xiang Fu — treats liver qi constraint with eye pain worsening at night
Nei Xiao Luo Li Wan (内消瘰疬丸): Xia Ku Cao, Zhe Bei Mu, Xuan Shen, Lian Qiao, Tian Hua Fen — resolves phlegm-fire and scrofula
Combined with Ju Hua, Gou Teng, Shi Jue Ming for liver yang hypertension headache

For liver fire with red painful eyes and headache: combine with Ju Hua, Jue Ming Zi, Long Dan Cao.
For scrofula and phlegm nodules (classical formula): combine with Zhe Bei Mu, Xuan Shen, Mu Li (Xiao Lei Wan).
For thyroid nodules and goiter: combine with Hai Zao, Kun Bu, Zhe Bei Mu.
For hypertension from liver yang rising: combine with Gou Teng, Tian Ma, Niu Xi.
For breast nodules and mastitis: combine with Pu Gong Ying, Jin Yin Hua, Gua Lou.
For liver-gallbladder fire with insomnia: combine with Zhi Zi, Dan Zhu Ye, Huang Qin.
For lymphoma adjunct therapy: combine with Ban Zhi Lian, Bai Hua She She Cao.

rosmarinic acid and rutin dilate blood vessels
- Antihypertensive: reduce BP
ursolic acid and betulinic acid
- Antitumor: induce apoptosis in lymphoma, breast, and liver cancer cells
Antibacterial
- active against Mycobacterium tuberculosis and Staphylococcus
prunellin
- Antiviral: inhibits HIV, herpes simplex, and influenza viruses
rosmarinic acid
- Anti-inflammatory: inhibits NF-κB and COX-2 pathways
polysaccharides
- Immunomodulatory: enhance NK-cell and macrophage activity
Thyroid-regulating
- reduces thyroid-stimulating antibody levels in Graves’ disease

Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs cold and heat, scrofula, rat fistula, head sores, breaks concretions, disperses goiter with bound qi, and foot swelling with damp impediment.’
Ben Cao Gang Mu (《本草纲目》): ‘Prunella Spike, for treating eye pain that worsens toward night — it is a miraculous herb. Also for cases where applying bitter-cold drops makes it worse — it is equally miraculous. For the eyeball connects to the root of the eye, which is the Liver system, belonging to the Jue Yin channel.’
Ben Cao Jing Shu (《本草经疏》): ‘Prunella Spike: bitter can drain binding, acrid can disperse binding, cold can eliminate heat — hence it governs cold-heat scrofula, rat fistula, and head sores.’
Dian Nan Ben Cao (《滇南本草》): ‘Expels Liver wind, moves through the channels and collaterals, treats deviation of mouth and eye, moves Liver qi, opens Liver depression, stops sinew and bone pain, eye pain, disperses scrofula, and systemic nodules.’