Folium Eucalypti Citriodorae
Aliases：Xiang An (Fragrant Eucalyptus); You An Shu (Oil Eucalyptus); Liu Xiang Jiu (Long-Lasting Fragrance); Lemon-Scented Eucalyptus; Yu Lin Mu (Fish-Scale Tree); Mao Tie Xiao; Jiao Er Meng.
Lemon Eucalyptus Leaf is the name of a traditional Chinese medicine. It is the leaf of Eucalyptus citriodora Hook. f. [syn. E. maculata Hook. var. citriodora (Hook. f.) Bailey], a plant in the family Myrtaceae. It is recorded in Guangxi Chinese Materia Medica, Fujian Materia Medica, Chinese Materia Medica, Guangxi Standards for Chinese Medicinal Materials, and other herbal works.
Efficacy & Actions
Dispels Wind and eliminates Dampness; fortifies the Stomach and relieves pain; removes toxin and relieves itching.
Indications
Wind-cold common cold; rheumatic bone pain; Wind-Dampness arthralgia; stomach Qi pain; food stagnation; sha distension with vomiting and diarrhea; diarrhea and abdominal pain; dysentery; asthma; malaria; sores and furuncles; wind rash; eczema; chronic tinea; scald and burn injuries; shellfire wounds (artillery wounds). Supplementary record in the Guangxi Standards for Chinese Medicinal Materials: influenza; epidemic cerebrospinal meningitis; measles; skin eczema.
Modern Pharmacology
Anti-inflammatory effect: The phenolic compounds in Lemon Eucalyptus leaves possess pronounced anti-inflammatory bioactivity. A study published in 2022 isolated ellagic acid and nine non-tannin compounds, including gallic acid, quercetin, and myricetin, from Lemon Eucalyptus leaves. Ellagic acid was confirmed in vivo to significantly prevent ethanol-induced gastric ulcers, indicating definite anti-inflammatory activity. A pharmacological study published in 2025 further confirmed that the leaves of Corymbia citriodora are rich in flavonoids and terpenoids and possess antioxidant and anti-inflammatory properties. Antibacterial and antifungal effects: The essential oil of Lemon Eucalyptus leaves exhibits significant inhibitory effects against various pathogenic bacteria. A comparative study of the antimicrobial activities of essential oils from three eucalyptus leaf samples produced in Guangxi showed that the essential oil of Lemon Eucalyptus leaves had the most prominent antimicrobial activity, with potential for application in food preservation. Gas chromatography-mass spectrometry (GC-MS) identified the main chemical constituents of Lemon Eucalyptus leaf essential oil as citronellal (55.31%), citronellol (21.03%), and isopulegol (10.79%). These constituents possess inhibitory effects against various fungi and bacteria. Antitumor effect: The essential oil of Lemon Eucalyptus leaves inhibits colon cancer in mice. In an experiment using a symmetrical dimethylhydrazine (DMH)-induced mouse colon cancer model, DMH produced a high tumor induction rate (81%) in Kunming mice. The histological characteristics and biological behavior of the induced colon cancer were relatively similar to those of human colon cancer, and the essential oil of Lemon Eucalyptus leaves exhibited antitumor effects. In addition, D-limonene, a constituent of Lemon Eucalyptus leaf essential oil, has also been reported to possess antitumor activity and can induce apoptosis in human colon cancer cells by inhibiting the PI3K/Akt pathway. Anti-tuberculosis effect: Lemon Eucalyptus leaves possess anti-tuberculosis activity. Analgesic effect: The essential oil of Lemon Eucalyptus leaves possesses analgesic activity. Antioxidant effect: The essential oil of Lemon Eucalyptus leaves possesses antioxidant activity.
Ingredients
The leaves and leafy young twigs of Lemon Eucalyptus mainly contain the following active constituents: Volatile oils (principal active constituents, content 0.5%–2.0%): Citronellal: the most abundant constituent in the essential oil, up to 83.26%, with most literature reporting a content of 55%–78%. Citronellol. Isopulegol. Neoisopulegol. Menthol. α-Pinene. β-Pinene. Myrcene. Linalool. Limonene. Geraniol. Citronellyl acetate. β-Caryophyllene. Cineole. Phenolic and tannin constituents: Ellagic acid. Gallic acid. 3-O-Methylellagic acid-4′-O-α-L-rhamnopyranoside. Flavonoids: Quercetin. Myricetin. Kaempferol, among others. Others: Eucalyptol. Citronellic acid. Resins, among others.
Usage & Dosage
Oral use: Decocted in water, 3–6 g. External use: Appropriate amount, decocted in water for external washing; or decocted in water for fumigation and washing of the affected area.
Contraindications
Use with caution in individuals with Yin deficiency and internal Heat. Lemon Eucalyptus Leaf is slightly warm in nature; its use by individuals with Yin deficiency and internal Heat may aggravate internal Heat patterns. Pregnant and breastfeeding women should use this product under the guidance of a physician. Not suitable for long-term or high-dose use. Use with caution in individuals with an allergic constitution; skin allergic reactions may occur with external use.
Selected Formulas
1、 For malaria (Fujian Materia Medica) Take 7 leaves of Lemon Eucalyptus (Corymbia citriodora). Decoct in water, then use the liquid to steep 1 egg or 1–2酥饼 (crispy cakes). Take 1–2 hours before the attack. 2、 For diarrhea, abdominal pain, sores, furuncles, and rheumatic impediment pain (New Veterinary Traditional Chinese Medicine) Take an appropriate amount of Lemon Eucalyptus leaves. Decoct in water and administer orally or use the decoction to wash the affected area. 3、 For dysentery (New Veterinary Traditional Chinese Medicine) Take an appropriate amount of Lemon Eucalyptus leaves. Decoct in water and administer orally. 4、 For various skin diseases and rheumatic bone pain (Guangxi Chinese Materia Medica) Take an appropriate amount of Lemon Eucalyptus leaves. Decoct in water and wash externally.
Medicinal Parts
Leaf.
Selection & Storage
Dried material should be stored in a cool, dry place. Protect from moisture and insect damage. Airtight storage is recommended. Avoid direct sunlight. Processing method: Remove impurities, cut into pieces, and dry in the shade.
