Er Chen Tang
Star二陈汤 (Two-Cured Decoction)
Source: Tai Ping Hui Min He Ji Ju Fang (Song, 1107)
Last updated August 30, 2026
Description
Er Chen Tang (Two-Cured Decoction) is the foundational formula for phlegm and damp in TCM. Its name refers to the two aged (chen) key herbs: Chen Pi and Ban Xia. Together they dry dampness, transform phlegm, regulate Qi, and harmonize the Stomach. As the basis for dozens of phlegm-treating formulas, Er Chen Tang is one of the most versatile base formulas in the TCM canon.
Composition
| Herb | Amount | % | Role | Function |
|---|---|---|---|---|
| Ban Xia | 12g | 33.33% | Jun (Chief) | Dries dampness, transforms phlegm, harmonizes Stomach. |
| Chen Pi | 9g | 25% | Chen (Deputy) | Regulates Qi, dries dampness, transforms phlegm. |
| Fu Ling | 9g | 25% | Zuo (Assistant) | Drains dampness, strengthens Spleen. |
|
Sheng Jiang
assistant and corrective assistant; as printed: Sheng Jiang (Zingiberis rhizoma recens)
|
3g | 8.33% | Zuo (Assistant) | helps dissolve phlegm and reduces the toxicity of Ban Xia |
|
Wu Mei
corrective assistant; as printed: Wu Mei (Mume fructus) 1 piece
|
1piece | 100% | Zuo (Assistant) | stabilizes Lung-Qi, balancing the pungent-warm dispersal of the formula |
| Gan Cao | 3g | 8.33% | Shi (Envoy) | Harmonizes all herbs, moderates drying. |
Total weight: 30g
Dui Yao — Core Herb Pairs
The classical two-herb combinations at the heart of this formula, as recorded on the herbs' own pages — each pair has an action neither herb has alone.
Drying damp and transforming phlegm combined with regulating qi, so that phlegm resolves as qi moves and the spleen is no longer burdened by dampness.
Foundation pairing for damp-phlegm cough with copious white sputum, chest oppression and nausea.
Energetics dose-weighted
The formula's overall nature, taste balance and channel reach, weighted by each herb's dose. Classical formulas often pair warm and cool herbs on purpose, so a net figure summarises the mix — it doesn't describe every herb in it.
Nature
Net slightly warm (+0.67)
From 100% of the weighed grams.
Grams by band: neutral 33%, warm 67%.
Taste
- pungent 54%
- sweet 21%
- bitter 13%
- bland 13%
From 100% of the weighed grams.
Channels reached
- Lung 100%
- Spleen 100%
- Stomach 50%
- Heart 33%
- Kidney 25%
Share of the grams entering each channel, from 100% of the weighed grams.
1 herb without a dose in grams, so left out of every figure above: Wu Mei.
Dose-weighted from each herb's recorded nature, taste and channels (missing values are left out, never counted as neutral). It describes the composition — it is not a recommendation.
Preparation
Decoct all herbs in water for 20–25 minutes. Take warm. Use with Sheng Jiang to enhance anti-nausea effect.
Dosage
Decoction: 1 dose/day in 2–3 doses. Pills: 6g 3x/day. Adjust based on severity.
Conditions Addressed
Related Formulas
Relationships
Full-screen graph →Click a node for details · double-click to expand it · Ctrl/⌘ + scroll or two fingers to zoom and pan.
Formula family
A catalogue formula counts as a core only when at least 80% of its herbs are present, no more than 1 is absent, and the absent herb is not its chief.
Formula Network
Formulas that share herbs with this one — the closer to the centre, the stronger the match. Click a node to explore.
Similar Formulas by composition
Match score combines dosage-weighted composition (cosine, 70%) with shared-herb overlap (Jaccard, 30%).
Traditional formula information is for educational purposes only. Herbal formulas should be prescribed by a qualified practitioner — dosages and combinations are individualized and can interact with medications.
📝 Notes
Public notes from the community and your own private notes on Er Chen Tang.
No notes yet.