Ze Xie Tang — Alisma Decoction

On this page

1. Overview
2. TCM pattern
3. Key herbs
4. Formula actions
5. Conditions treated
6. Comparisons with related formulas
7. Modifications
8. Cautions

Overview

Ze Xie Tang — the Alisma Decoction — is one of the simplest of Zhang Zhongjing’s formulas, appearing in the Jin Gui Yao Lue. Just two herbs — Ze Xie and Bai Zhu — in striking proportions (Ze Xie at five qian to Bai Zhu’s two qian). The formula targets the very specific picture of Phlegm-fluid stagnating in the middle burner producing dizziness and head heaviness.

Zhang Zhongjing’s short text reads: “When there is phlegm-fluid retained, the patient is dizzy in the head; Ze Xie Tang governs it.” Ze Xie powerfully drains accumulated fluid downward through the urine; Bai Zhu strengthens the Spleen so that the fluid is not re-generated. The formula is the foundation for many phlegm-fluid vertigo prescriptions.

I prescribe Ze Xie Tang as part of bespoke herbal formulas from pharmaceutical-grade granules sourced from Sun Ten in Taiwan.

TCM pattern

Ze Xie Tang is prescribed for Phlegm-fluid in the middle burner with dizziness:

• Dizziness — persistent, with a feeling of head being cloudy or heavy
• Sensation of the head being “wrapped”
• Vertigo with the floor moving
• Epigastric splashing sounds
• Mild palpitations
• Cough with thin clear sputum in some cases
• Reduced urination
• Tongue — pale, swollen, slippery white coat
• Pulse — slippery, deep

Key herbs

1. Ze Xie (Alisma plantago-aquatica) — chief, large dose; powerfully drains Damp downward through urination
2. Bai Zhu — tonifies Spleen and dries Damp; prevents re-generation

Formula actions

1. Drains Phlegm-fluid through urination
2. Strengthens the Spleen’s transformation of fluids
3. Lifts the head and resolves dizziness

Conditions treated

1. Phlegm-fluid vertigo — the primary indication
2. Ménière’s disease with prominent fluid accumulation
3. Vestibular migraine with phlegm-fluid pattern
4. BPPV recovery with lingering cloudy-headedness
5. Hypertension with phlegm-damp pattern — see high blood pressure
6. Hyperlipidaemia / high cholesterol — see how to lower cholesterol
7. Metabolic syndrome with fluid retention
8. Idiopathic intracranial hypertension — alongside neurological care
9. Persistent post-viral “brain fog” with phlegm pattern

Comparisons with related formulas

• Ban Xia Bai Zhu Tian Ma Tang — for Phlegm-Damp vertigo with prominent nausea; more comprehensive.
• Wu Ling San — for fluid retention with thirst and urinary symptoms.
• Xiao Ban Xia Jia Fu Ling Tang — for Phlegm-fluid with vomiting and palpitations.
• Ling Gui Zhu Gan Tang — for Phlegm-fluid with palpitations and chest fullness.

Modifications

• For prominent nausea, combine with Xiao Ban Xia Tang or use Ban Xia Bai Zhu Tian Ma Tang
• For prominent hypertension, add Tian Ma and Gou Teng
• For prominent Phlegm, add Ban Xia and Chen Pi
• For Spleen Qi deficiency overlay, add Ren Shen and Huang Qi
• For chronic use in metabolic syndrome, add Shan Zha and Dan Shen

Cautions

Vertigo and dizziness need medical assessment to exclude vestibular, neurological and cardiovascular causes. Sudden severe vertigo with neurological signs is a medical emergency — call 999.

Not appropriate for Yin-deficient dizziness (peeled tongue, night sweats, red tongue) or for Liver Yang rising patterns.

Generally well-tolerated in pregnancy under qualified supervision.

Always consult a qualified Chinese herbalist registered with the RCHM.

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