Er Chen Tang (Two Cured Decoction)

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Indications

Western Uses:

• What is Er Chen Tang used for in modern practice?

  In modern practice Er Chen Tang is referenced for conditions Western medicine associates with excess mucus/secretions and metabolic phlegm-damp, including chronic tracheitis and chronic bronchitis with copious sputum, pulmonary emphysema, and goiter/thyroid nodules — its traditional damp-phlegm indications mapped onto biomedical categories.

  These biomedical correlates describe the formula’s traditional use; they are not a claim that it treats, cures, or replaces medical care for any diagnosed respiratory or thyroid condition. Contemporary research (below) has also explored Er Chen Tang and its modifications for metabolic conditions such as hyperlipidemia and fatty liver, framed in TCM terms as phlegm-damp affecting fat and lipid metabolism; any such use belongs alongside a qualified practitioner and appropriate medical care, never in place of it.

  Source: Sacred Lotus sources & references + traditional-use correlates cross-checked against modern clinical literature (see research). Reference only, not a treatment claim.

Originally Appeared In:

• Imperial Grace Formulary of the Tai Ping Era (Tai Ping Hui Min He Ji Ju Fang)

Notes:

• How does Er Chen Tang relate to Wen Dan Tang, Ban Xia Bai Zhu Tian Ma Tang, and Liu Jun Zi Tang?

  Er Chen Tang is the base formula for damp-phlegm generally, and much of Chinese herbal medicine’s phlegm-formula family is built by adding herbs onto its core Ban Xia/Ju Hong (Chen Pi)/Fu Ling/Gan Cao structure. Recognizing it as the common ancestor makes several well-known formulas easier to understand.

  • Wen Dan Tang (Warm the Gallbladder Decoction): commonly understood as Er Chen Tang plus Zhi Shi and Zhu Ru, shifting the target from plain damp-phlegm to phlegm-heat disturbing the Gallbladder and Stomach — irritability, insomnia, and a bitter taste alongside the nausea and fullness.
  • Ban Xia Bai Zhu Tian Ma Tang: built from Er Chen Tang with Bai Zhu and Tian Ma added (plus supporting herbs in most versions), redirecting the formula toward wind-phlegm rising to disturb the head — dizziness and headache with a heavy sensation, rather than the cough/nausea picture of plain Er Chen Tang.
  • Liu Jun Zi Tang (Six Gentlemen Decoction): essentially Si Jun Zi Tang (Ren Shen, Bai Zhu, Fu Ling, Zhi Gan Cao — the classic Spleen-qi tonic) combined with Er Chen Tang’s Ban Xia and Chen Pi, for Spleen-Qi deficiency complicated by phlegm-damp (poor appetite, loose stools, and cough or nausea together).
  • Di Tan Tang and Dao Tan Tang: both add Zhi Shi (and Nan Xing/Dan Nan Xing) onto the Er Chen Tang base to scour more stubborn phlegm, with Di Tan Tang further adding Ren Shen and Shi Chang Pu for phlegm misting the Heart orifices.

  Classical source and lineage: Er Chen Tang first appears in the He Ji Ju Fang (Formulas of the Peaceful Benevolent Dispensary), the Imperial Pharmacy formulary compiled in the Song dynasty (printed 1107 CE), in its phlegm-damp category — one of the most influential formularies in the history of Chinese medicine, and the reason Er Chen Tang is taught as the template phlegm formula in most modern formula texts.

  Source: Bensky & Barolet, Formulas & Strategies; Chen & Chen, Chinese Herbal Formulas and Applications (formula-family relationships and classical source). Traditional-use framing.

Clinical Studies & Research:

• Is there modern research on Er Chen Tang?

  Yes — research on Er Chen Tang (Erchen Decoction) concentrates on lipid and metabolic effects, with supporting preclinical work on its anti-cancer and anti-inflammatory mechanisms. A 2024 meta-analysis pooling six randomized controlled trials (438 participants) found that Er Chen Tang used adjunctively significantly improved total cholesterol, triglycerides, LDL cholesterol, body mass index, and visceral fat area compared with control treatment, though the authors flagged a lack of high-quality, large-sample double-blind trials.

  • Obesity/dyslipidemia (clinical meta-analysis): 6 RCTs, 438 participants; significant post-treatment improvements in total cholesterol, triglycerides, LDL-C, BMI, and visceral fat area versus controls (PMID 38847686).
  • Hyperlipidemia (narrative review): synthesis of Chinese clinical trials reports comparable or superior lipid-lowering efficacy for modified Erchen Decoction versus standard statin therapy in several small studies, with proposed mechanisms spanning lipid metabolism, oxidative stress, and inflammatory signaling (PMID 39605912).
  • Metabolic disorders (preclinical, mouse): in high-fat-diet-fed C57BL/6 mice, Erchen Decoction lowered body weight, improved glucose tolerance and insulin secretion, and reduced triglycerides and cholesterol, with the effect linked to increased CDKAL1 gene expression (PMID 26504476).
  • Colorectal cancer (preclinical, network pharmacology + experimental validation): identified 116 active compounds and 12 hub targets, with Erchen Decoction suppressing colorectal cancer cell growth via cell-cycle arrest and apoptosis, acting on MAPK, PPAR, TP53, and STAT signaling pathways (PMID 36313338).

  Direct clinical-trial evidence remains concentrated in metabolic/lipid indications and is still limited by trial size and quality; the cancer and broader mechanistic findings are preclinical and do not establish a treatment effect in humans.

  Sources: PubMed 38847686 (Medicine (Baltimore), 2024); PubMed 39605912 (Frontiers in Pharmacology, 2024); PubMed 26504476 (Evidence-Based Complementary and Alternative Medicine, 2015); PubMed 36313338 (Frontiers in Pharmacology, 2022). Research context, not a therapeutic claim.