Ping Wei San: TCM's Classic Formula for Dampness in the Spleen and Stomach
Learn about Ping Wei San (平胃散), the essential TCM formula for drying dampness and revitalizing the Spleen. Understand its ingredients, clinical uses for bloating and digestive sluggishness, and how it differs from other dampness formulas.
What is Ping Wei San?
Ping Wei San (平胃散), meaning “Calm the Stomach Powder,” is the foundational TCM formula for treating dampness in the middle jiao — the Spleen and Stomach region. Recorded in the Song Dynasty text Taiping Huimin Heji Jufang (太平惠民和剂局方, Formulary of the Peaceful Benevolent Dispensary, 1151 CE), it has been the primary formula for drying dampness and harmonizing digestion for nearly 900 years.
If Er Chen Tang is the go-to for phlegm, Ping Wei San is the go-to for dampness in the digestive system — that heavy, bloated, sluggish feeling after eating, with a thick greasy coating on the tongue and a body that feels weighed down.
Understanding the Name
- Ping (平) — to calm, level, or harmonize
- Wei (胃) — the Stomach
- San (散) — powder, the original preparation form
The name captures the formula’s purpose: to calm and restore the Stomach by removing the dampness that disrupts its function.
The Pattern It Addresses
Ping Wei San treats Cold-Dampness obstructing the middle jiao (寒湿困脾). The Spleen in TCM is responsible for transforming food and fluids. When dampness accumulates, the Spleen becomes sluggish, digestion slows, and a cascade of symptoms appears.
Key Symptoms
- Fullness and distension in the abdomen and stomach area
- Loss of appetite or food tastes bland
- Nausea or vomiting
- Heavy sensation in the body and limbs — feeling weighed down
- Loose stools or sticky stools that are hard to flush
- Thick, greasy white tongue coating
- Sluggishness and fatigue — the mind feels foggy
- Belching with sour or stale taste
- Preference for warm drinks, aversion to cold drinks
The Ingredients
| Herb | Chinese | Amount | Role |
|---|---|---|---|
| Cang Zhu | 苍术 | 15 g | Chief — dries dampness, strengthens Spleen, aromatic to awaken |
| Hou Po | 厚朴 | 9 g | Deputy — moves Qi, resolves fullness, dries dampness |
| Chen Pi | 陈皮 | 9 g | Assistant — regulates Qi, dries dampness, transforms phlegm |
| Gan Cao | 甘草 | 6 g | Envoy — harmonizes, tonifies Spleen, moderates the drying herbs |
| Sheng Jiang | 生姜 | 3 slices | Assists — warms the middle, stops nausea |
| Da Zao | 大枣 | 2 pieces | Assists — protects the Spleen, moderates harshness |
How the Ingredients Work Together
Cang Zhu is the absolute star of this formula. Unlike Bai Zhu (White Atractylodes), which tonifies the Spleen gently, Cang Zhu (Black/Red Atractylodes) is powerfully drying and aromatic. Its strong aroma “wakes up” the Spleen, while its bitter-warm nature aggressively dries dampness. This makes it the primary herb whenever dampness is the dominant problem.
Hou Po (Magnolia Bark) addresses the bloating and fullness. Dampness obstructs Qi flow in the middle jiao, causing distension. Hou Po moves Qi downward and resolves stagnation, relieving the stuffed, heavy feeling.
Chen Pi (Aged Tangerine Peel) regulates Qi and assists in drying dampness. Its aged quality means it is gentle yet effective — it helps Qi flow without being harsh.
Gan Cao, Sheng Jiang, and Da Zao form a protective base that prevents the three strong drying herbs from damaging the Stomach. This is a classic TCM strategy: protect while you treat.
How It Differs from Er Chen Tang
Both formulas treat dampness, but they target different aspects:
| Feature | Ping Wei San | Er Chen Tang |
|---|---|---|
| Primary focus | Dampness in the Spleen/Stomach | Phlegm anywhere in the body |
| Main symptom | Bloating, heavy abdomen | Cough with sputum, nausea |
| Chief herb | Cang Zhu (drying) | Ban Xia (phlegm-transforming) |
| Tongue coating | Thick, greasy, white | White, greasy, may be slippery |
| Key complaint | ”I feel heavy and bloated" | "I have phlegm and nausea” |
| Best for | Digestive dampness | Respiratory or systemic phlegm |
Clinical Applications
Primary Indications
- Functional dyspepsia — bloating, early fullness, heavy stomach
- Chronic gastritis with damp-cold pattern
- IBS with constipation (sticky, incomplete stools)
- Loss of appetite from dampness (common in humid climates or after illness)
- Nausea and vomiting from cold-damp in the Stomach
Extended Applications
| Condition | Notes |
|---|---|
| Hangover or overindulgence | Dries dampness from rich food and alcohol |
| Morning sickness (cold-damp type) | When nausea is worse with cold drinks |
| Pediatric digestive issues | Children with poor appetite and sticky stool |
| Chronic fatigue (damp type) | Fatigue with heavy limbs and greasy tongue |
| Post-illness sluggishness | When the digestive system is slow to recover |
Modern Relevance
Ping Wei San is exceptionally relevant today because modern dietary habits create exactly the dampness pattern it treats:
- Cold drinks and ice — impair Spleen function
- Dairy and greasy foods — generate dampness
- Sedentary lifestyle — Qi stagnation leads to dampness accumulation
- Air conditioning — external cold damages Spleen Yang
- Eating too fast or while stressed — impairs digestion
Japanese Kampo medicine uses this formula extensively (as Shōbakusan) for functional gastrointestinal disorders, and it is one of the most prescribed Kampo formulas in Japan.
Dosage and Administration
- Decoction: Simmer herbs in water for 20–30 minutes. Take warm, 30 minutes before or after meals
- Powder (traditional form): Mix 3–6 g of finely ground powder with warm water or rice soup
- Granules: 6–9 g dissolved in warm water, twice daily
- Patent pills: Available as Ping Wei Wan; follow manufacturer dosing
- Duration: 1–4 weeks for acute dampness; longer for chronic patterns
Cautions and Contraindications
- Yin deficiency — if you have dry mouth, dry throat, night sweats, and a tongue with little or no coating, this formula will worsen the dryness
- Stomach Fire — red tongue with yellow dry coating, burning in the stomach, strong thirst
- Pregnancy — the strong drying herbs should be used with caution
- Dehydration or fluid deficiency — this is a drying formula; do not use when fluids are already depleted
- Not for Heat-type diarrhea — if diarrhea is burning, foul-smelling, and with urgency, a heat-clearing formula is more appropriate
Related Articles
- Er Chen Tang: Classic Phlegm Formula — compare with Ping Wei San
- Chen Pi (Aged Tangerine Peel) — key ingredient in this formula
- Licorice (Gan Cao) — harmonizer of the formula
- Dampness in TCM — understand the Dampness pathogen
- TCM Dietary Therapy — foods that cause and treat dampness
- TCM Digestive Health — comprehensive gut health guide
FAQ
Who is this article for?
This article is for readers who want a practical, beginner-friendly understanding of this TCM formula.
Can this article replace professional medical advice?
No. This content is educational only and should not replace diagnosis or treatment from a qualified healthcare professional.
Disclaimer
This content is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment.