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Monograph Library

Black Walnut Hull Capsules


One of several walnut or Juglansspecies, black walnut is a deciduous tree indigenous to the eastern seaboard of North America. Although it has a rich-tasting, edible nut, its use as a food source has been superseded by the English or common walnut (Juglans regia). This is because the kernels of the common walnut are larger and have a shell that is easier to crack. Walnuts are a richly nutritious functional food, full of healthful protein, fatty acids, tryptophan, and other elements.[1] Much of the research on the benefits of walnut centres on the common walnut, which has been used as a food source and medicine from the earliest times in classical antiquity. Its unripe nut, for example, has been valued for its worm-killing and skin-healing virtues.[2],[3]


In broad terms, the Juglans genus has generated a substantial body of research that points to its wide range of significant therapeutic properties. These include antitumor, antioxidant, antibacterial, and anti-inflammatory qualities, not to mention its role as a protective agent against cardiovascular issues.[4]


Black walnut in particular is now attracting more interest from researchers.[5] This has led to interesting speculation about its potential therapeutic benefits in treating cardiovascular disease, cancer, and neurodegenerative disorders.[6] The fruit of the black walnut consists of a husk, hard shell, and kernel. Research shows that the kernel abounds in health-promoting phenolic compounds.[7] The husk too contains a concentration of these compounds and is demonstrably antioxidant and antimicrobial.[8],[9] The phenolics in the husk include chlorogenic acid, caffeic acid, ferulic acid, sinapic acid, gallic acid, ellagic acid, protocatechuic acid, syringic acid, vanillic acid, catechin, epicatechin, myricetin, and juglone.[10]

Black walnut capsules out on a white table


Research indicates that juglone, which is a distinctively green naphthoquinone, is demonstrably antimicrobial and is as effective in dealing with fungus as some commercially available medicinal treatments.[11] Juglone is, in fact, a broad spectrum bactericidal agent.[12] In addition, in vitro and in vivo studies (i.e. test tube and lab animal studies respectively) suggest that juglone inhibits the growth of tumors.[13] Synthetic derivatives of juglone have demonstrated anti-proliferative (i.e. tending to inhibit cell growth) activity in rats against malignant gliomas, which are aggressive and life-threatening tumors that affect the brain and spinal cord and come with a poor prognosis.[14] Small wonder that it is the juglone in black walnut that makes the tree what’s called allelopathic. This term means that it excretes chemicals into its environment, in this case juglone, that cause other plants in its vicinity to wilt and die.[15] It should be noted that, while juglone is derived from the green unripe hulls of black walnut, it oxidizes quickly when exposed to air and changes colour to brown.

In an early study on mice, injections of ellagic acid, juglone, and other acids and alkaloids from black walnut hulls were found to significantly depress tumor growth rate.[16] In other early research conducted on mice, injections of ellagic acid from black walnut caused a lowering of blood pressure and an elevation in T wave (i.e. a recovery of the action of the ventricle of the heart), as well as having sedative action and being protective against mortality after electroconvulsive shock.[17] Indeed, later research has further demonstrated ellagic acid as derived from walnut to be cardioprotective.[18] Ellagic acid is, moreover, a known anticarcinogenic plant phenol.[19] In a recent in vitro study, a combination of walnut phenols, including catechin, chlorogenic acid, ellagic acid, and gallic acid was shown to suppress colon cancer.[20]


The indigenous peoples of North America used green black walnut hulls topically as an antifungal against ringworm.[21] The Eclectics, physicians of the 19thand early 20thcenturies who tended to rely on herbal remedies, recognized these dermatological virtues of black walnut and treated it as botanically similar to the common walnut.[22] Peter Holmes, the well-known specialist in classic Oriental medicine, shares this unitary approach to these two walnut species and points out that walnut’s bitter naphthoquinones enjoy antifungal and anti parasitic activity. He also makes an intriguingly thought-provoking reference to the ancient doctrine of signatures, i.e. the notion that a plant’s physical characteristics are apt to resemble the human body part it is meant to nourish and heal. Following this line of thought, he points out how the walnut resembles both the brain and the intestines, both of these being physical systems of the body that are fed by the walnut’s rich store of minerals and nutrients.[23]

Herbalist Michael Tierra explains that black walnut hull extract is good for skin diseases and is antifungal, antiparasitic, and effective against dysentery.[24] In an excellent popular article on black walnut, writer Tamra Orr cites H. Winter Griffith M.D., formerly an associate professor of Family and Community Medicine at the University of Arizona’s College of Medicine, as asserting that black walnut hull does indeed help with a range of health conditions, including intestinal parasites and tapeworms, skin conditions, and fungal infections.[25],[26]

It has been noted by herbalist Dr. John R. Christopher that black walnut hulls enjoy a heavy concentration of potassium iodide.[27] An analysis by research chemist Mark Pedersen confirms this,[28] as does Steven H. Horne, who remarks that black walnut is one of only a handful of land plants that contains a rich store of iodine. Which is why Horne considers black walnut a significant remedy for serious thyroid problems. He reports too that fibromyalgia often responds to black walnut use, explaining that the condition may be partially attributed to iodine deficiency.[29]

In the end, there’s every good reason why the closely botanically related English walnut, the standard bearer for black walnut and the various nut-bearing species in this genus, has a Latin name that means “royal nut.”

For information on getting rid of parasites check out our monograph on Ear oil and how you can help keep the right bacteria's in your body

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Who is it for

  • Those suffering from pinworms, tapeworms, and other intestinal parasites
  • Anyone dealing with ringworm, athlete’s foot, and candida
  • People with skin conditions


How it helps

  • A classic antiparasitic
  • Antifungal properties
  • Richly antioxidant and antibacterial


[1] - Dongdong Bi et al, “Phytochemistry, Bioactivity and Potential Impact on Health of Juglans: the Original Plant of Walnut,” Natural Product CommunicationsMarch; 11(6): 869-880.

[2] - Mrs. M Grieve, A Modern Herbal, Vol. 2, New York: Dover, 1971 [reprint of 1931 edition], pp. 842-845.

[3] - W.T. Fernie, Herbal Simples Approved for Modern Uses of Cure, Bristol: John Wright, 1895, pp. 387-391.

[4] - Dongdong Bi et al, op.cit.

[5] - It has been found that black walnut contains higher levels of monounsaturated fatty acids and antioxidants such as polyphenols and g-tocopherol than does the common walnut. Cf. Cristiane Rodrigues Silva Camara and Vicki Schlegel, “A Review on the Potential Human Health Benefits of the Black Walnut: A Comparison with the English Walnuts and Other Tree Nuts,” International Journal of Food Properties2016 June; 19(10): 2175-2189.

[6] - Camara and Schlegel, op.cit.

[7] - Danh Vu et al, “Identification and Characterization of Phenolic Compounds in Black Walnut Kernels,” Journal of Agricultural and Food Chemistry 2018 May; 66(17): 4503-4511

[8] - Jonathan Wenzel et al, “Antioxidant potential of Juglans nigra, black walnut, husks extracted using supercritical carbon dioxide with an ethanol modifier,” Food Science and Nutrition2016 May; 5(2): 223-232.

[9] - In their study of black walnut, Camara and Schlegel, op.cit., infer a higher concentration of polyphenols in the walnut hull from an earlier study on common walnut: T. Fukuda et al, “Antioxidative polyphenols from walnut (Juglans regia L.),” Phytochemistry2003; 63: 795-801.  

[10] - F. Stampar et al, “Traditional walnut liqueur – cocktail of phenolics,” Food Chemistry 2006 April ; 95(4): 627-631.

[11] - Alice Clark et al, “Antimicrobial activity of juglone,” Phytotherapy Research 1990 February; 4(1): 11-14.

[12] - D.A. Wright et al, “Naphthoquinones as broad spectrum biocides for treatment of ship’s ballast water: toxicity to phytoplankton and bacteria,” Water Research2007 March; 41(6): 1294-1302.

[13] - K.B. Aithal et al, “Tumor growth inhibitory effect of juglone and its radiation sensitizing potential: in vivo and in vitro studies,” Integrative Cancer Therapies2012 March; 11(1): 68-80.

[14] - Valeria Pavan et al, “Antiproliferative activity of Juglone derivatives on rat glioma,” Natural Product Research 2017 March; 31(6): 632-638.

[15] - “Black Walnut Toxicity,” West Virginia University Extension Service,

[16] - U.C. Bhargava and B.A. Westfall, “Antitumor activity of Juglans nigra (black walnut) extractives,” Journal of Pharmaceutical Sciences1968 October; 57(10): 1674-7.

[17] - U.C. Bhargava et al, “Preliminary pharmacology of ellagic acid fromJuglans nigra(black walnut),” Journal of Pharmaceutical Sciences1968 October; 57(10): 1728-1732.

[18] - Z. Papoutsi et al, “Walnut extract (Juglans regia L) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483,” British Journal of Nutrition2008 April; 99(4): 715-722.

[19] - John L. Maas et al, “Ellagic Acid, an Anticarcingoen in Fruits, Especially in Strawberries: A Review,” HortScience1991 January; 26(1): 10-14.

[20] - J. Lee et al, “Walnut Phenolic Extract and Its Bioactive Compounds Suppress Colon Cancer Cell Growth by Regulating Colon Cancer Stemness,” Nutrients2016 July; 8(7): pii: E439.

[21] - Daniel E Moerman, Native American Ethnobotany, Portland, OR:Timber Press, 1998; pp. 280-281.

[22] - W.T. Fernie, op.cit.

[23] - Peter Holmes, The Energetics of Western Herbs, Vol. 2, Revised Second Edition,  Boulder, CO: Snow Lotus Press, 1994, pp. 657-660.

[24] - Michael Tierra, The Way of Herbs, New York: Pocket Books, 1998, p. 206.

[25] - Tamra B. Orr, “Black walnut: Promising health benefits are all they’re ‘cracked’ up to be with this nut,” Health in Balance, 1999 March, p. 44, found online at:

[26] - H. Winter Griffith, M.D., Vitamins, Herbs, Minerals and Supplements: The Complete Guide, Tucson, AZ: Fisher Books, 1998, as cited by Tamra Orr.

[27] - JR Christopher, School of Natural Healing, Provo, UT: BiWorld Publishers, Inc.; 1976.

[28] - Mark Pedersen, Nutritional Herbology: A Reference Guide to Herbs. Warsaw, IN: Wendell W. Whitman Company; 1994, pp.50-51.

[29] - S Horne, “Black Walnut,” Nature's Field2006; 22(9):1-2.

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