Bark of Largeleaf Chinese Ash

Chinese
秦皮
Pinyin
Qin Pi
Latin
Cortex Fraxini

TCM Properties

Taste
bitter
Temperature
cold
Channels
Gallbladder, Stomach, Large Intestine, Liver

Traditional Use

Primary Actions

  • Clears damp-heat from the intestines - a classic bark for diarrhea, dysentery, abdominal urgency, and foul stools when heat and dampness lodge in the Large Intestine.
  • Astringes and contains damp-heat discharge - used for leukorrhea and chronic damp-heat seepage where the herb's bitter, cooling, and mildly restraining qualities help dry and hold at the same time.
  • Clears Liver heat and improves vision - classically valued for red, swollen, painful eyes or hot eye discharge, especially when intestinal damp-heat and liver heat coexist.
  • Resolves toxic-heat irritation without the harshness of more drastic purgatives - useful when heat must be dried and cleared but the patient still needs some containment rather than strong downward draining.

Secondary Actions

  • Often decocted as an external wash for hot, irritated eyes, extending its use beyond internal gastrointestinal patterns.
  • Because it is both cold and somewhat astringent, Qin Pi is frequently chosen in lingering intestinal or genital damp-heat rather than in very acute excess that needs a stronger purgative strategy.

Classic Formulas

  • Bai Tou Weng Tang (白头翁汤) - from Shang Han Lun, where Qin Pi assists in clearing toxic-heat dysentery with abdominal pain, tenesmus, and blood or pus in the stool.
  • Qin Pi Tang (秦皮汤) - later traditional decoction variants built around Qin Pi for either damp-heat dysentery or red painful eye disease, reflecting the herb's dual intestinal and ophthalmic roles.
  • Classical eye-wash preparations frequently combine Qin Pi with Ju Hua and other cooling herbs when damp-heat or Liver heat inflames the eyes.

Classical References

  • Shen Nong Ben Cao Jing lists Qin Pi among the bitter-cold heat-clearing barks, a foundation for its later use in dysentery and hot eye disease.
  • TCM Wiki and Me & Qi both preserve the standard profile of Qin Pi as bitter and cold, entering the intestines and liver-related channels to clear damp-heat while also addressing ocular inflammation.
  • Later clinical traditions emphasize that Qin Pi is especially useful when damp-heat diarrhea and lower-burner discharge persist long enough to require both clearing and a light restraining quality.

Modern Research

Active Compounds

  • Esculin (coumarin glycoside) - one of the best-known marker compounds in Qin Pi bark with anti-inflammatory relevance
  • Esculetin (coumarin aglycone) - widely studied for anti-inflammatory, antioxidant, and dermatologic effects
  • Fraxin (coumarin glycoside) - contributes anti-inflammatory and antimicrobial activity
  • Fraxetin (coumarin derivative) - linked with antioxidant and vascular-protective research
  • Fraxicoumarin and related isocoumarins - recently characterized bark constituents with anti-inflammatory activity

Studied Effects

  • Recent review literature summarizes antibacterial, anti-inflammatory, antioxidant, anticancer, neuroprotective, and anti-hyperuricemic activities across the medicinal Fraxinus species recognized in Chinese pharmacopoeia (PMID 40067772)
  • Anti-inflammatory bark constituents - fraxicoumarin and related isocoumarins from Fraxinus chinensis subsp. rhynchophylla inhibited nitric oxide, iNOS, and COX-2 signaling in activated macrophages (PMID 31960706)
  • Esculetin from Fraxinus rhynchophylla attenuated atopic skin inflammation and reduced inflammatory cytokine expression in experimental dermatitis models (PMID 29656211)
  • Antimicrobial studies on bark-derived coumarins support the traditional use of Qin Pi in heat-toxin and damp-heat disorders involving microbial overgrowth (PMID 28976788)

PubMed References

Safety & Interactions

Contraindications

  • Spleen and Stomach deficiency-cold with chronic loose stools
  • Absence of damp-heat or liver-heat signs

Cautions

  • Its bitter-cold nature can weaken appetite or aggravate cold digestion if used too long in depleted patients
  • Because Qin Pi has a mild astringing quality, it is better matched to damp-heat dysentery than to early external-stage disorders that still need pathogen release
  • MSK page not found - drug interaction data not available from Memorial Sloan Kettering integrative medicine database

Conditions