Stops bleeding and promotes tissue repair - used for bleeding trauma, ulcerated sores, and lesions that need both rapid hemostasis and restoration of damaged tissue.
Astringes sores and dries damp exudation - applied externally for weeping eczema, chronic ulcers, oral ulceration, and damp erosive lesions that are slow to close.
Moves Blood locally and relieves traumatic swelling - a common role in powders and trauma preparations where bruising, seepage, and pain occur together.
Can be used internally in small doses for heat irritation in the mouth and throat - a secondary use that relies on its cool astringent character rather than bulk detoxifying action.
Secondary Actions
Hai Er Cha is not a separate species from Er Cha; it is an alternate trade and prescription name for the same catechu extract preserved as a second record because of the import split.
Like Er Cha, it is mainly used as a powder, pill ingredient, or topical substance rather than as a long-decocted crude herb.
Classic Formulas
Qi Li San (七厘散) - classic trauma powder using catechu to assist bleeding control and tissue healing while companion herbs move Blood and reduce pain.
Long Gu Er Cha San (龙骨儿茶散) - external powder tradition for damp weeping eczema and ulcerative lesions where catechu helps dry, astringe, and regenerate tissue.
Classical References
TCM Wiki lists Hai Er Cha, Hei Er Cha, and Er Cha as overlapping names for black catechu and assigns the same traditional actions of stopping bleeding, promoting regeneration, and treating trauma.
Me and Qi notes that pharmacopoeial black catechu is sourced from Acacia catechu and cautions that similar trade blocks are not always identical in origin.
IMPORT NOTE: This `-2` file is a synonym record rather than a distinct herb, retained because the spreadsheet imported the alternate pinyin Hai Er Cha.
Modern Research
Active Compounds
Catechin (flavan-3-ol) - the dominant marker polyphenol and the main driver of catechu's astringent pharmacology profile
Epicatechin (flavan-3-ol) - major companion catechin with antioxidant and anti-inflammatory relevance
Epigallocatechin and epicatechin gallate derivatives (polyphenols) - part of the richer phenolic composition described in Acacia catechu reviews
Gallic acid and protocatechuic acid (phenolic acids) - linked to antioxidant and antimicrobial effects
Condensed tannins and procyanidins (tannins) - likely central to the drying, tightening, and wound-protective actions of catechu preparations
Studied Effects
Species-level review literature on Acacia catechu supports antimicrobial, anti-inflammatory, antioxidant, antiulcer, and wound-healing activity, closely matching the traditional Er Cha and Hai Er Cha profile (PMID 36432824)
Antimicrobial activity - Acacia catechu extract inhibited multiple bacterial and fungal strains in vitro, supporting the external use of catechu on vulnerable skin and mucosal lesions (PMID 22282602)
Wound-healing benefit - Acacia catechu showed significant diabetic-wound healing activity in animal models, aligning with the classical claim that catechu promotes new flesh generation (PMID 37693096)
Phytochemistry-focused review work continues to emphasize catechin-rich phenolics as key contributors to antiproliferative, antioxidant, and inflammatory-pathway effects (PMID 40981159)