Black Walnut
JuglandaceaeJuglans nigra
Also known as: Eastern Black Walnut, American Walnut, Black Walnut Hull
clinical_notes Clinical Summary
Black Walnut (Juglans nigra) is an Eastern North American hardwood tree whose green hull is used medicinally as an antiparasitic, antifungal, and antimicrobial herb.
The primary active constituent juglone (5-hydroxy-1,4-naphthoquinone) disrupts parasite cellular metabolism, inhibits key fungal enzymes, and demonstrates antibacterial activity in vitro.
Human clinical trials are lacking; evidence is primarily from in vitro studies and traditional use.
It is a classic component of three-herb antiparasitic protocols alongside wormwood and cloves.
Short-term use only is recommended; contraindicated in pregnancy and tree-nut allergy.
Pregnancy Safety
Contraindicated in pregnancy. Juglone and naphthoquinone compounds are potentially harmful to the developing fetus. No use during pregnancy.
Lactation Safety
Insufficient safety data. Avoid medicinal preparations during breastfeeding.
warning Contraindications
- Pregnancy (contraindicated)Theoretical
- Tree nut allergy (contraindicated)Clinically Proven
- Long-term internal use (avoid)Theoretical
vital_signs Clinical Profile
Primary Indications
- check_circle intestinal parasites
- check_circle candida overgrowth
- check_circle fungal skin infections
- check_circle tinea
- check_circle chronic skin conditions
- check_circle constipation
- check_circle diarrhea (tannin astringency)
- check_circle bacterial skin infections
Therapeutic Actions
System Affinities
- check_circle gastrointestinal
- check_circle integumentary
- check_circle immune
- check_circle hepatic
labs Active Constituents
juglone
plumbagin
ellagic acid
gallic acid
ellagitannins
galloylglucose
juglansregia glycosides
oleic acid
linoleic acid
beta-carotene
vitamin C
history_edu Traditional Use
No TCM data available for this herb yet.
Traditional Uses Across Healing Systems
While many herbs lack controlled clinical trials, centuries of traditional practice across cultures provide valuable insight into their therapeutic applications.
Cherokee: bark tea as laxative and for toothache; poultice for skin eruptions, ringworm, and infected wounds; nut eaten as nutritious food
Multiple Native American tribes including Cherokee, Comanche, and others used different parts of the black walnut for distinct medicinal purposes. Introduced to Europe in 1629.
Antiparasitic protocol herb (with wormwood and clove); antifungal for candida, tinea, and athlete's foot; alterative for chronic skin conditions; mild laxative
A cornerstone of the Hulda Clark antiparasitic protocol (green hulls with wormwood and cloves). Nicholas Culpeper documented walnut in his Complete Herbal (1653). Rosemary Gladstar included antifungal powder using black walnut hulls.
spa Parts Used
hull
- intestinal parasites
- candida
- fungal skin infections
- antimicrobial
Green (unripe) hull used for maximum juglone content - up to 10x higher than mature hull. Prepared as tincture (1:5, 50% ethanol) or hull powder. Short-course use (2-4 weeks) recommended; commonly used in antiparasitic protocols with wormwood and cloves.
leaf
- skin conditions
- antimicrobial topical
- astringent for diarrhea
Leaves used as infusion or decoction for topical applications. Astringent tannin content makes it useful for diarrhea and topical skin conditions.
shield Safety
Contraindications — Evidence Basis
Pregnancy
Juglone and other naphthoquinone compounds are contraindicated in pregnancy. Potential to cause uterine contractions. Avoid all medicinal preparations of black walnut hull during pregnancy.
Tree nut allergy
Black walnut is a tree nut and will trigger allergic reactions in people with tree nut allergies. May cross-react with other walnuts, pecans, and related nuts.
Long-term internal use
Juglone is a potent naphthoquinone that can be irritating and potentially toxic with prolonged internal use. Short courses (2-3 weeks) are the traditional practice.
Toxicity
Juglone (isolated) is toxic to many organisms at low concentrations. Whole hull preparations are generally safer with short-term use at standard doses.
Nausea, vomiting, diarrhea with excessive internal use; contact dermatitis from hull (stains skin dark brown/black); potential hepatotoxicity with prolonged high-dose use
Discontinue. For GI symptoms: supportive care. For contact dermatitis: wash affected area thoroughly; topical corticosteroids if severe.
Adverse Effects
CYP Metabolism
Juglone is a known inhibitor of multiple enzymes. Limited CYP interaction data in humans. Theoretical interactions with hepatically metabolized drugs cannot be excluded.
swap_horiz Interactions
Oral Medications with Narrow Therapeutic Index (Tetracyclines, Fluoroquinolones, Levothyroxine, Digoxin, Warfarin)
Class: Narrow Therapeutic Index Drugs
Black walnut hull contains very high concentrations of tannins (ellagitannins and gallotannins) that bind to various drugs in the gastrointestinal tract, forming drug-tannin complexes that are poorly absorbed. This physical chelation can significantly reduce the bioavailability of co-administered medications.
Administer all narrow therapeutic index medications at least 2 hours before or 4 hours after black walnut hull supplements. Do not take black walnut products with antibiotics, thyroid medications, or cardiac drugs. Monitor drug efficacy when co-administration occurs.
Iron Supplements (Ferrous Sulfate, Ferric Carboxymaltose, Iron Sucrose)
Class: Iron Supplements
The ellagitannins and other polyphenols in black walnut hull strongly chelate iron in the gastrointestinal tract, forming insoluble iron-tannin complexes. Studies show that high-tannin foods and supplements can reduce non-heme iron absorption by 50-80% when consumed simultaneously.
Always separate black walnut hull supplements from iron supplementation by at least 2 hours. This interaction is particularly important in patients with iron-deficiency anemia or those who have undergone gastrointestinal surgery. Monitor hemoglobin and ferritin levels if concurrent use continues.
Anticoagulants / Antiplatelet Agents (Warfarin, Aspirin, Clopidogrel, Heparin)
Class: Anticoagulant / Antiplatelet
Black walnut kernels are rich in alpha-linolenic acid (omega-3 fatty acid) and vitamin E, both of which have antiplatelet and mild anticoagulant properties. High-dose supplementation may additively increase bleeding risk when combined with anticoagulants or antiplatelet drugs.
Monitor for unusual bruising or bleeding in patients on anticoagulant therapy who consume large amounts of black walnut. Discontinue high-dose black walnut supplementation 2 weeks before surgery. Culinary nut consumption at typical dietary amounts carries minimal interaction risk.
Antidiabetic Agents (Metformin, Insulin, Glipizide)
Class: Antidiabetics
Chlorogenic acid in black walnut kernels inhibits ROS generation and improves insulin sensitivity, with beneficial effects on glycemia in animal models. Dietary walnut intake has shown modest improvements in glucose metabolism. Additive glucose-lowering effects may occur with concurrent antidiabetic medications.
Monitor blood glucose in diabetic patients on antidiabetic medications who consume substantial black walnut quantities. Hypoglycemia risk is low but advise awareness of symptoms. Dietary walnut consumption is generally beneficial in diabetes management.
Lithium (Lithium Carbonate, Lithium Citrate)
Class: Mood Stabilizer
Black walnut's high tannin and mineral content may affect absorption of lithium when taken together. Additionally, black walnut has mild diuretic properties that could influence sodium and lithium renal clearance, with potential risk of altering lithium serum levels.
Monitor lithium levels if a patient on lithium begins regular consumption of black walnut supplements. Advise against taking black walnut hull products at the same time as lithium doses. Separate administration by at least 2 hours.
hub Combinations
Synergistic pairings can enhance therapeutic outcomes, while knowing suitable substitutes helps when specific herbs are unavailable or contraindicated.
Classical Formulas
2Clove
Traditional UseThird component of classic antiparasitic triad. Clove (eugenol) is active against parasite eggs and larvae, complementing Black Walnut (adult parasites) and Wormwood (larvae and adult stages).
Classic herbal antiparasitic protocol; traditional and integrative medicine consensus use.
Wormwood
Traditional UseClassic antiparasitic triad component. Black Walnut (juglone) disrupts parasite cell metabolism; Wormwood (absinthin/thujone) impairs parasite GABA receptors; together provide complementary antiparasitic coverage.
Traditional herbal protocol popularized by Hulda Clark; used by integrative clinicians for intestinal parasite protocols. Limited formal RCT data.
science Studies
Profiling Anticancer and Antioxidant Activities of Phenolic Compounds Present in Black Walnuts (Juglans nigra) Using a High-Throughput Screening Approach
In VitroThis in vitro high-throughput screening study profiled phenolic compounds from multiple black walnut cultivars for anticancer activity against a panel of human cancer cell lines and antioxidant capacity. The study systematically characterized the relationship between specific phenolic compound profiles and biological activities across cultivars. Significant anticancer and antioxidant activities were identified, with variation correlating to cultivar-specific compound profiles. The research provides scientific foundations for understanding the pharmacological basis of black walnut's traditional use and identifies candidate compounds for further drug development.
Black Walnut (Juglans nigra) Extracts Inhibit Proinflammatory Cytokine Production From Lipopolysaccharide-Stimulated Human Promonocytic Cell Line U-937
In VitroThis in vitro study used metabolomic profiling to identify potential anti-inflammatory compounds across 10 black walnut cultivars and then tested five selected cultivars on the human promonocytic U-937 cell line. LPS-stimulated human immune cells were exposed to methanolic extracts at four concentrations (0.1-10 mg/mL) and cytokine/chemokine expression was measured by flow cytometric multiplex assay. Black walnut extracts significantly suppressed LPS-induced production of multiple pro-inflammatory cytokines, with differences in potency observed among cultivars. The study demonstrates dose-dependent anti-inflammatory activity of black walnut kernel extracts and identifies cultivar-specific variation in bioactive compound profiles.
medication Dosing
tincture
5-10 mL (1:4, 25% ethanol of green hull)
TID for 2-4 weeks
Short course only (2-4 weeks maximum). Use green hull tincture for highest juglone concentration. Commonly combined with wormwood and cloves in antiparasitic protocols.
capsule
500-1000 mg green hull powder
1-2x/day for 2-3 weeks
Short-course use only. Ensure product specifies green hull not mature hull for maximum juglone content.
Disclaimer: This information is largely AI-generated and reviewed by human experts at Evara Health. It is intended for educational and clinical reference purposes only and should not replace professional medical advice.
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