Gua Lou Pi (Trichosanthes Peel, Snake Gourd Peel)

Chinese Herb Actions

Chinese Herb Dosage

• What is the dosage of Gua Lou Pi?

  6–12 g in decoction — and unusually, both of the reference ranges held here agree exactly. Chen gives 6–12 g in decoction and Bensky gives 6–12 g in decoction, so there is no range to reconcile on this herb.

  • Form — the peel is normally supplied cut into pieces or shreds and decocted in the ordinary way; it needs no special handling comparable to the late addition used for aromatic herbs.
  • Choosing the peel over the whole fruit — the whole fruit (Gua Lou) is dosed higher in the classical chest formulas on this site, where 12–30 g is specified; the peel is a lighter, more qi-moving choice at a lower dose.
  • Dose limits are secondary to the incompatibility rule — see the cautions below, which matter more in practice than the exact gram figure.

  Source: Sacred Lotus sources & references (dosage field, with both recorded reference ranges, and the whole-fruit formula amounts, as held on file). Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• What should not be taken with Gua Lou Pi?

  Gua Lou Pi is one of the classical Eighteen Incompatibilities: it is not combined with aconite. The caution held here reads “do not use with Wu Tou,” and that name covers the whole aconite group. Checked against the incompatibility links recorded on this site, the peel is flagged against all three aconite herbs held — Fu Zi (processed aconite), Chuan Wu (prepared Sichuan aconite) and Cao Wu (prepared wild aconite).

  • The rule covers the entire family, not just the peel. Twelve incompatibility pairings are recorded across this plant on the site — each of the four members (Gua Lou, Gua Lou Pi, Gua Lou Ren and Tian Hua Fen) against each of the three aconites. In other words, choosing a different part of the trichosanthes plant does not get round the rule.
  • Spleen and Stomach deficiency — the other caution held here. It is a sweet, cold herb, and cold herbs sit badly on a weak, cold digestion; loose stools and poor appetite are the signals to avoid it.
  • Cold-phlegm and damp-phlegm coughs — this is a phlegm-heat herb; a cough with copious clear or white sputum from cold is the opposite pattern.
  • Best used under a qualified practitioner, and the aconite incompatibility in particular is a prescribing rule rather than a self-care caution.

  Source: Sacred Lotus sources & references (this herb’s cautions field and the recorded herb-incompatibility links for the whole Trichosanthes family against Fu Zi, Chuan Wu and Cao Wu, as held on file); cross-referenced against multiple online sources and materia medica consensus on the Eighteen Incompatibilities. Reference note, not a safety guarantee.

Chinese Herb Toxicity & Overdose

• None Noted

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Gua Lou Pi (Trichosanthis Pericarpium)?

  Yes — and it points in a direction the traditional indication anticipates: the chest. Most of the clinical literature concerns a Chinese hospital injection preparation of the peel used alongside conventional care in angina pectoris. A meta-analysis of 14 randomised trials in 1,621 patients reported that the injection added to conventional therapy improved clinical and electrocardiographic outcome measures compared with conventional therapy alone, with mild adverse reactions reported in eleven studies and no serious adverse drug reactions; the authors called for larger, more rigorously designed multi-centre trials.

  • Read the preparation carefully. That evidence concerns an injectable extract given in hospital, not the decocted herb, and it is drawn largely from Chinese-language trials of variable quality. It is context for the traditional chest indication, not a treatment claim for the dried peel.
  • Cough and airway work (animal). The peel-and-root herb pair was screened for its optimal ratio in a zebrafish inflammation model and then tested in an ammonia-induced cough model in mice, where the 1:2 combination reduced cough frequency and lengthened cough latency. The same pair has also been studied in a COPD model with microbiome and metabolomic analysis.
  • Chemistry of the peel specifically. Recent isolation work from the pericarps has described megastigmane sesquiterpenoids and monoterpenoid and cucurbitane-type triterpenoid constituents with anti-complementary and anti-inflammatory activity in vitro, and a novel pericarp polysaccharide has been structurally characterised and studied in a diabetic-nephropathy model.
  • Cardiac preclinical work — the peel preparation has been examined in isoproterenol-induced acute myocardial ischaemia and in cardiac-fibrosis models in rats. Animal research only.

  The overall picture is a genuine and active research literature that clusters around the chest and airway — but the human evidence is limited to one injectable dosage form and needs stronger trials before anything can be concluded.

  Sources: PMID 29956895, DOI 10.1016/s0254-6272(17)30020-1 (meta-analysis, 14 trials, 1,621 patients); PMID 38173907, PMC 10758601, DOI 10.4330/wjc.v15.i12.633 (retrospective clinical study); PMID 37634750, DOI 10.1016/j.jep.2023.117096 (peel-root ratio, zebrafish and cough-mouse models); PMID 40845001, PMC 12373185, DOI 10.1371/journal.pone.0330621 (peel-root pair, COPD model); PMID 40614872, DOI 10.1016/j.fitote.2025.106715 and PMID 37418785 (pericarp constituents, anti-complementary activity); PMID 41014623, DOI 10.1002/cbdv.202403380 (pericarp polysaccharide); PMID 29842965, DOI 10.1016/j.jep.2018.05.034 (family review). Research context, not a therapeutic claim.

Chinese Herb Notes

• What is the difference between Gua Lou Pi, Gua Lou, Gua Lou Ren and Tian Hua Fen?

  All four are the same plant — Trichosanthes kirilowii — held here as four separate medicinals because four different parts of it do four different jobs. Three come from the fruit; the fourth, Tian Hua Fen, is the root, which almost nobody guesses from the name. Gua Lou Pi is the peel, and it is the part weighted toward moving qi and opening the chest.

  • Gua Lou Pi (栝楼皮, Pericarpium Trichosanthis Kirlowii) — the peel or rind. Sweet, cold; Lung, Stomach, Large Intestine. It regulates qi and opens the chest and it is not lubricating. Chosen when the problem is chest constraint with phlegm-heat but without marked dryness, or where a loosening effect on the stool would be unwelcome.
  • Gua Lou Ren (栝楼仁, Semen Trichosanthis Kirlowii) — the seed. Same nature, flavour and channels, but it is the oily part and is weighted the other way: the strongest of the family at moistening a dry Lung and loosening dry stool.
  • Gua Lou (栝楼, Fructus Trichosanthis Kirlowii) — the whole ripe fruit, peel and seed together, so it does both jobs at once. It is the form specified in Xiao Xian Xiong Tang, Bei Mu Gua Lou San and the chest-opening decoction held here with Xie Bai.
  • Tian Hua Fen (Trichosanthis Kirlowii Radix) — the root. Bitter, slightly sweet, cold; Lung and Stomach only. Not really a phlegm herb in the same sense: it clears heat and generates fluids for thirst and wasting-and-thirsting patterns, and reduces swelling and expels pus for sores.

  The shortest version: peel opens the chest, seed moistens, whole fruit does both, root generates fluids.

  Peel and root are also a recognised pair. Trichosanthis Pericarpium with Trichosanthis Radix — peel plus root of the same plant — has been studied in its own right as a herb pair for cough with lung heat, and the pairing is associated with Bei Mu Gua Lou San, which on this site is recorded with the whole fruit (Gua Lou 3 g) alongside Tian Hua Fen 2.4 g, Chuan Bei Mu 4.5 g, Fu Ling, Ju Hong and Jie Geng — two members of this family in one formula. (Traditional formula context, not treatment advice.)

  Botanical naming: current botanical usage writes the plant Trichosanthes kirilowii Maxim., while the pharmaceutical Latin recorded here uses the spelling “Kirlowii” across all four family records. The Chinese pharmacopoeia also admits Trichosanthes rosthornii Harms as a source plant for the fruit, peel, seed and root, so commercial material may derive from either species. This is a species-and-spelling point rather than a conflict between sources, and the identity fields have been left exactly as held.

  Source: Sacred Lotus sources & references (herb records for all four family members and the formula-ingredient records naming them, as held on file); cross-referenced against multiple online sources and materia medica consensus; family scope per PMID 29842965, DOI 10.1016/j.jep.2018.05.034; peel-and-root herb pair per PMID 37634750, DOI 10.1016/j.jep.2023.117096.

This herb is incompatible with:

• Fu Zi (Radix Lateralis Praeparatus Aconiti Carmichaeli)
• Cao Wu (Radix Aconiti Kusnezoffii Preparata)
• Chuan Wu (Radix Aconiti Preparata)