Scientific Names of European Walnut Leaf:

Juglans regia L. and J.  nigra L. [Fam. Juglandaceae]


Infusions and tinctures made from the leaves, bark and husks of walnut species.

Traditional Usage:

– Anthelminthic
– Anti-candidiasis
– Antifungal
– Anti-inflammatory
– Antiviral
– Astringent
– Eczema
– Glandular Disorders
– Hemorrhoids
– Herpes simplex
– Hypothyroidism
– Immune System
– Gallbladder Problems
– Liver Health Maintenance
– Poultice
– Scabies
– Skin Disorders
– Ulcers (external)


The leaves of English walnut trees, Juglans regia L. [Fam. Juglandaceae], also known as European walnut, have been used medicinally for thousands of years particularly for treating skin disorders. English walnut is native to southeastern Europe, Asia Minor, India and China. The leaves, bark and husks of black walnut, Juglans nigra L., native to North America, have also been used traditionally as medicines by American Indians and later by European settlers. The bark of black walnut was chewed for toothaches and the inner-bark was used as a laxative. The fruit-husk was chewed for colic, the juice used on ringworm and poulticed for inflammation. The leaves are considered astringent, and insecticidal against bedbugs and mites (i.e. scabies). The famous herbalist, Nicholas Culpeper, used European walnut to “kill worms in the stomach or belly”. The juice of the green husk was boiled with honey and used as a gargle for sore mouth and throat and to relieve heat and inflammation in the throat and stomach. Walnut leaf today is most often used externally as an astringent for treating eczema, herpes and ulcers. The leaves of black walnut are most often used to treat hemorrhoids as well as liver and gallbladder problems. In folk medicine, black walnut leaf was also given to relieve headache, hepatitis, and skin conditions, although there is little evidence to back up these claims. Black walnut juice is believed to cure herpes, eczema, and worms. The compound, juglone, isolated from black walnut, has been shown to be a laxative, fight worms, and have strong activity against bacteria and abnormal growths. Dr. James Duke recommends eating walnuts for treating various glandular disorders including thyroid problems and notes studies showing that the fresh juice of green walnuts made by boiling them for about 20 minutes, boosted thyroxine at least 30 percent.

Active Ingredients:

English walnut leaves contain: approximately 10% tannins of the ellagitannins type; 0.001-0.03% essential oil with germacrene D as the main component; naphthalene derivatives especially the monoglucosides of juglone (5-hydroxy-1,4-naphtholquinone) and hydrojuglone; over 3% flavonoids including quercetin and kaempferol; 0.8-1.0% ascorbic acid; plant acids including gallic, caffeic and neo-chlorogenic acids.
According to Lillie J. Martin black walnut leaves contain tannin as the dominant principle; volatile oil, a volatile acid, resin, wax, gum, and a crystallizable substance, probably a glucoside. The ash constituted 8.5 per cent, and the absence of aluminum in the ash was established. (Amer. Jour. Pharm., 1886, p. 468). Black walnut fruit have been shown to contain methyl 2-benzimidazolylcarbamate.

Suggested Amount:

English walnut leaf decoctions for external use are prepared using 2-3 g dried leaf per 100ml cold water. The cut leaf is placed in cold water and brought to a boil and simmered for about 15 minutes. The decoction is used in compresses, poultices and partial baths. Blumenthal and other (2000) note that occlusive dressings and/or topical applications of walnut decoctions to large areas of the body should be avoided. Currently the advised application of walnut leaf based on the German Commission E extends only to external use. However, health authorities in France permit the use of walnut leaf for oral use. Based on Turkish folk medicine, decoctions of the green husks or leaves of walnut species for internal use in the treatment of glandular disorders including thyroid problems are made by boiling the plant material for about 20 minutes. Dr. James Duke in The Green Pharmacy recommends eating walnuts for low dosages – alternatively the leaf decoction can also be used for boosting glandular functioning. For treating Candida, Dr. Duke recommends a tincture made largely from fresh black walnut husks together with a few drops each of tinctures of lavender flowers, valerian root, pau-d’arco and teatree oil.

Drug Interactions:

None known.


None known.

Side Effects:

None known when used as directed. However, isolated juglone may be mutagenic and carcinogenic and therefore internal use of black walnut preparations is not recommended for extended periods or in high dosage until further studies of its therapeutic effects and potential toxicity have been carried out. Toxicity of black walnut heartwood–apparent allergies to man and horse-has been documented. Oral (intragastric) dosing with an aqueous extract of black walnut heartwood (Juglans nigra) to horses induces acute laminitis (primarily in the forefeet) within 4 to 12 hours after administration. The extract causes perfusion of blood to the foot and edema to outlined regions within the foot. In one study, black walnut heartwood extract reversibly enhanced the vasoconstriction induced in isolated blood vessels by administration of epinephrine potentiated with hydrocortisone. In contrast, aqueous extracts made, using the same techniques, from the shavings of eastern white pine (Pinus strobus), Eastern red cedar (Juniperus virginiana), and pin oak (Quercus palustrus) had no effect on epinephrine-induced digital vessel contractions. [MacDaniels LH. Perspective on the black walnut toxicity problem–apparent allergies to man and horse. Cornell Vet. 1983 Apr; 73(2): 204-7].


Blumenthal M, Goldberg A, Brinckmann J 2000. Herbal Medicine: Expanded Commission E Monographs. Copyright American Botanical Council. Publ. by Integrative Medicine Communications, 1029 Chestnut Street, Newton, MA 02464. Pp. 401-403.

Cline S, Felsot A, Wei L. Determination of methyl 2-benzimidazolylcarbamate in black walnut fruit. J Agric Food Chem. 1981 Sep-Oct; 29(5): 1087-8.

Duke, J. 1997: The Green Pharmacy, The Ultimate Compendium of Natural Remedies from the World’s Foremost Authority on Healing and Herbs. Pp. 248; 334; 463; 481. Rodale Press.

Foster S, and Duke JA. 1990. Black Walnut in Medicinal Plants. Houghton Mifflin Co., New York, NY, p. 276.

Galey FD, Whiteley HE, Goetz TE, Kuenstler AR, Davis CA, Beasley VR. 1991. Black walnut (Juglans nigra) toxicosis: a model for equine laminitis. J Comp Pathol. 1991 Apr; 104(3): 313-26.