Supplement analysis backed by scientific evidence · PT

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Limited evidenceImmunity

Loquat Leaf

Eriobotrya japonica leaf, a fixture of Chinese and Japanese cough syrups such as pipa gao. The pharmacology is well described but human trials are essentially absent.

Evidence last reviewed: August 2026

What the science says

  • Cough and airway inflammation Limited evidence

    Evidence is confined to animal and mechanistic work: a study in a cough-variant asthma model found loquat leaf water extract reduced airway inflammation. No randomised controlled trial in people with cough has been published.

  • Traditional use and constituents Limited evidence

    A review of the traditional uses, phytochemistry and pharmacology of loquat leaves catalogues triterpenes such as ursolic and corosolic acid with anti-inflammatory activity in laboratory models. Laboratory activity is not clinical benefit.

  • Metabolic effects Limited evidence

    Loquat leaf is also marketed for blood sugar on the strength of corosolic acid, but human data are limited to small, low-quality studies. Treat any glycaemic claim as unproven.

Dosage & safety

Studied doseNo dose established in humans. Traditional decoctions use 6-12 g of dried leaf daily; commercial syrups do not usually state the extract amount.
SafetyLoquat seeds and, to a lesser extent, leaves contain cyanogenic glycosides, so stick to prepared products and stated doses. Fine hairs on the underside of raw leaves can irritate the throat and are traditionally removed. Little safety data in pregnancy, breastfeeding or children; syrups are often high in sugar or honey and are unsuitable for infants under one year.

Scientific references

Where to buy

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