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.

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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.

How to take it

TimingTraditionally split through the day during a cough; no evidence favours a time.

With food?Either way.

Worth knowingStick to prepared products at stated doses rather than raw leaf — the seeds and leaves carry cyanogenic glycosides, and syrups are unsuitable for babies under one because of the honey or sugar.

Frequently asked questions

Does loquat leaf help a cough?

Loquat leaf has limited evidence for cough: only animal and mechanistic studies exist, such as one showing reduced airway inflammation in a cough-variant asthma model. No randomised controlled trial in people with cough has been published.

Does loquat leaf lower blood sugar?

Loquat leaf blood sugar claims rest on corosolic acid, with human data limited to small, low-quality studies. Treat any glycaemic claim for loquat leaf as unproven.

Is loquat leaf syrup safe for children?

Loquat leaf syrups such as pipa gao are often high in honey or sugar and are unsuitable for babies under one year, and there is little safety data in children. Stick to prepared products at stated doses, because loquat seeds and leaves carry cyanogenic glycosides.

How much loquat leaf should I take?

No human dose of loquat leaf has been established; traditional decoctions use 6–12 g of dried leaf daily, and commercial syrups rarely state the extract amount.

Scientific references

Traditional uses, phytochemistry, pharmacology, and toxicity of Eriobotrya japonica leaves: A summary
Zhu X, Wang L, Zhao T — J Ethnopharmacol, 2022
Theory of the exterior-interior relationship between the lungs and the large intestine to explore the mechanism of Eriobotrya japonica leaf water extract in the treatment of cough variant asthma
He Q, Liu C, Shen L — J Ethnopharmacol, 2021

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