Pang Da Hai (Boat Sterculia Seed)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Pang Da Hai?

  Two to five seeds — it is counted, not weighed. Our record carries both standard figures: 3–5 seeds in decoction (Chen) and 2–3 pieces in decoction (Bensky). It is one of the few herbs routinely dosed by piece count, because the seeds are large, light and swell enormously, so a weight in grams would be misleading.

  • Decoction / infusion — 2–5 seeds, per the two reference sources.
  • Steeped as a tea — the common everyday preparation: the whole seeds are steeped in hot water rather than boiled hard, and the resulting mucilage is drunk.
  • Allow room — each seed swells to many times its dry volume into a soft spongy mass, so a small covered cup will overflow. Use a large vessel.

  Note: the two recorded ranges differ slightly (3–5 vs 2–3 seeds). This is editorial convention between materia medica rather than a factual conflict; both are reported rather than averaged.

  Source: our own herb record (both recorded ranges); published materia medica consensus. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Pang Da Hai?

  Use caution where there is diarrhea or loose stools — it is cold and it moistens the intestines, so it can loosen the bowels further. That is the caution our record carries, and it is the one that matters in everyday use, because the herb is often taken casually as a tea by people who would not think of it as medicine.

  • Loose stools or diarrhea — caution; the bowel-moistening action works against you here.
  • Spleen deficiency with cold — a sweet cold herb is poorly suited to a cold, weak digestion, particularly taken daily over long periods.
  • Not for every sore throat — it addresses hot, dry throat patterns. A sore throat from an external cold pattern, or one that is severe, persistent or accompanied by fever or breathing difficulty, needs proper assessment rather than a throat tea.
  • Long-term daily use — the herb’s toxicological profile has had little study (see research), so extended daily use is not something the literature can vouch for.

  Source: our own herb record (diarrhea/loose stool caution); published materia medica consensus; PMID 30322606 for the gap in toxicological study. Reference disclosures, not usage instructions.

Chinese Herb Toxicity & Overdose

• Low at ordinary doses; our record notes that possible overdose symptoms include poor balance and respiratory depression. Those are overdose observations, not effects expected from a few seeds steeped as a tea — but they are the reason the herb is dosed by seed count and not taken by the handful.

  The honest position on the wider safety picture is that it has not been well studied. A comprehensive pharmacological review of this herb concludes that “few studies have been done in the areas of quality control, pharmacokinetics, and toxicological studies” (PMID 30322606). Absence of reported harm at food-like doses is not the same as demonstrated long-term safety.

  Source: our own herb record (overdose symptoms); PMID 30322606, DOI 10.1016/S1875-5364(18)30112-2 (review noting the toxicology and quality-control gap). Reference note, not a safety guarantee.

Herb-Drug Interactions

• No well-established clinical herb–drug interactions are documented. One general, mechanism-free caution applies to any strongly mucilaginous herb: bulk-forming, gel-forming material taken at the same time as oral medication can in principle slow or reduce its absorption, so separating doses by an hour or two is a common-sense precaution rather than a documented interaction. (Precautionary; flagged for practitioner confirmation.)

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

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

• What plant is Pang Da Hai, botanically?

  Our record gives the pharmaceutical Latin as Sterculiae lychnophorae Semen — the dried ripe seed of Sterculia lychnophora Hance. In current botanical nomenclature the accepted name of that plant is Scaphium affine (Mast.) Pierre, with Sterculia lychnophora treated as a synonym. A review of the herb states this directly: the seeds of Scaphium affine are “known as Pangdahai (PDH) in Chinese and recorded as Sterculia lychnophora Hance (scientific synonym) in the 2015 edition of the Chinese Pharmacopeia” (PMID 30322606). Both names refer to the same seed; the pharmacopoeial name simply lags the botanical revision. Our identity field is therefore consistent with the pharmacopoeia and is left unchanged; the modern binomial is noted here so readers searching either name land in the right place. The tree is native to Southeast Asia, and the seed is used in Chinese, Japanese, Vietnamese, Thai and Indian traditional medicine.

  Is there modern research on Pang Da Hai (Sterculia lychnophora)?

  Yes — a modest but coherent preclinical literature centred on the seed’s polysaccharides, with no clinical trial evidence. Nothing below is a medical claim.

  • Review of the whole field — a 2018 ethnopharmacology, phytochemistry and pharmacology review is the best single entry point. It reports that the traditional uses for pharyngitis, constipation and pain are the ones justified by pharmacological studies on the polysaccharides and aqueous extracts, and that the organic (ethanolic and methanolic) extracts show anti-inflammatory, anti-ulcer, antipyretic, antimicrobial, anti-obesity and analgesic effects but have received comparatively little attention. It also flags the shortage of quality-control, pharmacokinetic and toxicological work (PMID 30322606; DOI 10.1016/S1875-5364(18)30112-2).
  • Oral and antimicrobial — ethanol extracts inhibited Streptococcus mutans growth and biofilm formation in a dose-dependent manner in vitro, which the authors attributed to the alkaloid, phenolic, glycoside and peptide fractions (PMID 27190540; PMC 4852106).
  • Chemistry — two alkaloids, sterculinine I and II, were isolated alongside thirteen known compounds from the seed (PMID 12770602); a 2024 study combining biosynthetic pathway analysis with molecular networking plausibly identified 126 constituents (PMID 38706424; DOI 10.1002/pca.3369).
  • Metabolic — an inhibitory effect on fatty acid synthase has been reported (PMID 18380011), a laboratory finding only.

  There are no published human clinical trials establishing efficacy for the throat, voice or bowel uses. Treat the research as chemistry and mechanism.

  Sources: PMID 30322606, DOI 10.1016/S1875-5364(18)30112-2 (ethnopharmacology/phytochemistry/pharmacology review; Scaphium affine synonymy; polysaccharide evidence; toxicology gap); PMID 27190540, PMC 4852106, DOI 10.1155/2016/8163150 (antibacterial and antibiofilm activity against S. mutans); PMID 12770602, DOI 10.1016/s0031-9422(03)00182-1 (sterculinine alkaloids); PMID 38706424, DOI 10.1002/pca.3369 (comprehensive constituent characterisation); PMID 18380011 (fatty acid synthase inhibition, preclinical). Research context, not a therapeutic claim.

Chinese Herb Notes

• Why does Pang Da Hai swell up in water?

  Because the seed coat is rich in mucilage — polysaccharides that absorb many times their own weight in water. A dry seed roughly the size of a large olive expands within minutes into a soft, translucent, spongy mass that fills a cup. This is the origin of the name “fat big sea,” and it is not a defect or a sign of spoilage. The swelling is also the point: the same mucilage that expands in the cup is what coats and soothes a dry throat and what lubricates the intestines. A pharmacological review of this herb notes that its water decoctions “largely contain very polar constituents like polysaccharides” and that the traditional uses for pharyngitis, constipation and pain are the ones best supported by studies on those polysaccharides and aqueous extracts (PMID 30322606).

  Is Pang Da Hai the throat tea sold in the West?

  Yes — it is widely sold outside China as a throat or voice tea, often under names referencing singers and speakers. Our own record already carries the practitioner note that it suits singers and speakers with sore throat or hoarseness, and this is the form most Western readers meet it in: whole seeds steeped in hot water, sometimes with honey or with liquorice. It is a mild, food-adjacent herb, which is why it made that crossover when stronger throat herbs did not.

  How does Pang Da Hai differ from other throat herbs?

  • Pang Da Hai — sweet and cold, moistening; the choice for a dry hot throat with hoarseness or lost voice, and it moves the bowels as a side benefit.
  • Jie Geng (Platycodon root) — opens and lifts Lung qi and expels phlegm from the throat; not moistening in the same way.
  • She Gan (Belamcanda rhizome) — bitter and cold, directed at throat swelling and pain with phlegm-heat; stronger and more draining.
  • Niu Bang Zi (burdock fruit) — releases the exterior as well as benefiting the throat; the choice when there is an active wind-heat presentation.

  Formula context: our own formula records do not currently link Pang Da Hai to any formula, so no formula is named here.

  Source: our own herb records (Pang Da Hai, Jie Geng, She Gan, Niu Bang Zi) and our own formula records; published materia medica consensus; PMID 30322606, DOI 10.1016/S1875-5364(18)30112-2 for the polysaccharide/aqueous-extract point. Traditional context, not treatment advice.