Er Chen Tang — Two-Cured Decoction

Overview

Er Chen Tang — Two-Cured Decoction — is the foundational formula for resolving Phlegm-Damp in Chinese herbal medicine. Named after its two principal aged and processed herbs (Ban Xia and Chen Pi), it dates to the Song Dynasty and serves as the base from which dozens of derivative Phlegm-resolving formulas are built. Phlegm-Damp is an extremely common pathological product generated by weak Spleen function, poor diet and sedentary lifestyle, making Er Chen Tang one of the most frequently modified base formulas in clinical use.

TCM pattern

Prescribed for Phlegm-Damp obstructing the Middle Jiao, characterised by: cough with copious white or grey phlegm, nausea, a sensation of fullness in the chest and epigastrium, dizziness, palpitations, a swollen tongue with thick greasy white coating, and a slippery (Hua) pulse.

Key herbs

Ban Xia (Pinellia ternata rhizome, processed) — the principal herb; dries Dampness, transforms Phlegm, descends Rebellious Qi and stops nausea
Chen Pi (aged Citrus reticulata peel) — regulates Qi, dries Dampness and transforms Phlegm
Fu Ling (Poria cocos) — tonifies Spleen Qi and leaches out Dampness, addressing the root cause of Phlegm production
Zhi Gan Cao (honey-fried Glycyrrhiza root) — tonifies Spleen Qi and harmonises the formula
Sheng Jiang (fresh Zingiber officinale rhizome) — warms the Middle and assists Ban Xia in drying Dampness
Wu Mei (Prunus mume fruit) — astringes and prevents the drying herbs from damaging Yin

Conditions treated

Respiratory conditions with Phlegm-Damp cough — chronic bronchitis, COPD and recurrent chest infections with copious phlegm
Nausea and vomiting from Phlegm-Damp, including morning sickness in pregnancy (in modified form)
IBS and digestive disorders with Phlegm-Damp obstructing the Middle Jiao
Dizziness and vertigo from Phlegm-Damp rising to disturb the head
Fatty liver disease — as part of complex formulas for Phlegm-Damp accumulation