Pi Pa Ye (Loquat Leaf)

Chinese Herb Actions

Chinese Herb Dosage

• What is the dosage of Pi Pa Ye, and why must it be wrapped?

  Roughly 6–15 g of the dried leaf in decoction — our references give 6–15 g (Bensky) and 10–15 g dried or 15–30 g fresh (Chen & Chen) — and it is decocted wrapped in cloth. Wrapping is not optional fussiness: it is how the fine hairs on the underside of the leaf are kept out of the finished decoction.

  • Dried leaf — 6–15 g (Bensky); 10–15 g (Chen & Chen).
  • Fresh leaf — 15–30 g (Chen & Chen).
  • Wrapped in cloth (bao jian) — standard for this herb, because residual leaf hairs suspended in the liquid irritate the throat.

  Source: Sacred Lotus sources & references (Bensky; Chen & Chen); cross-referenced against multiple online sources. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Pi Pa Ye?

  Yes — Pi Pa Ye is a cooling, descending herb, so it is contraindicated wherever the pattern is cold. It is otherwise a mild, well-tolerated herb; the main practical caution is the leaf hairs rather than any systemic risk.

  • Cough due to Cold — do not use; the herb is bitter and cool and will not suit a cold pattern.
  • Nausea or vomiting due to Stomach Cold — do not use.
  • Unprocessed leaf — leaf hairs that are not removed, or leaf that is decocted unwrapped, can irritate the throat and aggravate coughing. Use de-haired leaf, wrapped.
  • Weak Spleen with loose stools — use with care, as with cold-natured herbs generally.

  Source: Sacred Lotus sources & references (Bensky; Chen & Chen); cross-referenced against multiple online sources.

Chinese Herb Toxicity & Overdose

• Low. The comprehensive review of Eriobotrya japonica leaves reports that high doses of leaf extracts have been used in laboratory animals with no side effects or toxicity symptoms observed. PMID 35870687. No significant toxicity is recorded for the leaf at standard decoction doses in the sources reviewed.

  The realistic hazard is mechanical rather than chemical: the fine hairs on the leaf underside are throat irritants, which is why de-hairing and wrapped decoction are standard practice for this herb.

  Source: PMID 35870687; Sacred Lotus sources & references (Bensky; Chen & Chen). Reference note, not a safety guarantee.

Herb-Drug Interactions

• No well-established clinical herb–drug interactions are documented for Pi Pa Ye in the literature reviewed. Preclinical work on triterpene constituents of loquat leaf reports glucose-lowering effects in cell and animal models — corosolic acid in particular. PMID 30867526; PMC 6416347. On that basis, practitioner awareness is reasonable for patients on glucose-lowering medication; this is precautionary reasoning from preclinical pharmacology, not a demonstrated clinical interaction. (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.

• Is there modern research on Pi Pa Ye (Eriobotrya japonica leaf)?

  Yes — a large preclinical literature centred on the leaf’s triterpene acids and flavonoids, including work that maps directly onto its traditional antitussive use. Human clinical evidence for the leaf as a single herb remains limited.

  • Comprehensive review — 164 compounds have been identified from loquat leaves, including triterpenes, flavonoids, sesquiterpene glycosides, megastigmane derivatives, phenylpropanoids and organic acids, plus 169 volatile oil constituents. Triterpenes and flavonoids are identified as the main bioactive classes, with reported antidiabetic, anti-inflammatory and antitumour activity, and additional reported antitussive, expectorant, bronchodilatory and tracheal-smooth-muscle-relaxing effects. PMID 35870687.
  • Cough model (animal) — loquat leaf water extract reduced cough number, prolonged cough latency and lessened airway remodelling in a mouse model of cough variant asthma, with effects linked to the MMP-9/TIMP-1 pathway and to changes in intestinal flora. Oleanolic and ursolic acid content of the extract was verified by HPLC. PMID 34438032.
  • Anti-inflammatory — leaf extract showed anti-inflammatory and anti-arthritic activity in experimental models. PMID 31770567.
  • Triterpene constituents — corosolic acid isolated from loquat leaves reduced glucose levels in hepatocellular carcinoma cells, zebrafish and rats. PMID 30867526; PMC 6416347.
  • Chemistry by plant part — metabolomic profiling comparing different parts of Eriobotrya japonica and their biological activities. PMID 33992354.

  This is cell, animal and chemical work. It provides context for the traditional indications; it is not evidence of clinical efficacy and is not a therapeutic claim.

  Sources: PMID 35870687; PMID 34438032; PMID 31770567; PMID 30867526 / PMC 6416347; PMID 33992354.

Chinese Herb Notes

• How is Pi Pa Ye prepared, and when is the honey-fried form used?

  Pi Pa Ye must be processed before use: the dense fine hairs on the underside of the leaf are brushed or scraped off, and the leaf is then used either raw or honey-fried (mi zhi). This is the detail most often left out of online descriptions, and it is the one that determines both tolerability and which of the herb’s two roles you get.

  • Removing the hairs — the underside of a loquat leaf is covered in fine trichomes. If they are not removed (and if the leaf is not also decocted wrapped), they irritate the throat and can provoke the very cough the herb is given for. De-haired leaf is the standard medicinal form.
  • Honey-fried Pi Pa Ye (mi zhi pi pa ye) — the honey-prepared form is moistening and is the choice when the emphasis is on the Lung: cough, especially dry or lingering cough. Honey-frying moderates the leaf’s bitter coolness.
  • Raw (unprepared) Pi Pa Ye — retains more of its clearing, descending character and is the choice when the emphasis is on Stomach heat with nausea, vomiting or hiccups.
  • How it differs from neighbouring herbs — where Xing Ren descends Lung qi and moistens the intestines, and Sang Bai Pi drains Lung heat and promotes urination, Pi Pa Ye is the one that descends both Lung and Stomach qi — the herb to reach for when a heat cough and rebellious Stomach qi appear together.
  • Classical formula context — Pi Pa Ye appears in Qing Zao Jiu Fei Tang (Eliminate Dryness and Rescue the Lungs Decoction), for dry, warm pathogens injuring the Lung. (Traditional formula context, not treatment advice.)

  Source: Sacred Lotus sources & references (Bensky; Chen & Chen) and Sacred Lotus formula cross-reference; cross-referenced against multiple online sources.