Carya, Carya basilike, Carya persica, Green Black Walnut, Green Walnut, Juglans nigra, Jupiter's Nuts, Nogal Americano, Nogal Negro, Nogueira-preta, Noix, Noix de Jupiter, Noix de Perse, Noix Verte, Noyer d'Amérique, Noyer Noir, Noyer Noir Américain, Nux persica, Nux regia, Schwarze Walnuss, Walnoot, Walnut.


Overview Information

Black walnut is a tree. The fruit (nut) is often eaten as a food. The nut, the shell of the nut (hull), and the leaf are sometimes used to make medicine.

Black walnut is eaten as part of the diet to lower the risk of heart disease, but there is no good scientific evidence to support this use.

How does it work?

Black walnut contains high concentrations of chemicals called tannins, which can reduce pain and swelling and dry up body fluids such as mucous.


Uses & Effectiveness?

Insufficient Evidence for

  • Heart disease. Eating 1.5 ounces of nuts, such as black walnut, per day as part of a low-fat, low-cholesterol diet may help prevent heart disease. But research is limited.
  • Leukemia.
  • Diphtheria.
  • Syphilis.
  • Intestinal worms.
  • Use as a gargle.
  • Skin wounds.
  • Other conditions.
More evidence is needed to rate the effectiveness of black walnut for these uses.

Side Effects

Side Effects & Safety

When taken by mouth: The fruit (nut) of black walnut is LIKELY SAFE for most people when eaten in the amounts found in food. There isn't enough reliable information to know if the leaf or the shell of the nut (hull) are safe to use as medicine. These parts of the plant contain chemicals called tannins. Taking too much tannin can cause stomach upset and kidney and liver damage. The bark is POSSIBLY UNSAFE. Taking the bark daily might increase the risk for tongue or lip cancer.

When applied to the skin: Black walnut is POSSIBLY UNSAFE. It contains a chemical called juglone that can irritate the skin.

Special Precautions & Warnings:

Pregnancy and breast-feeding: The fruit (nut) of black walnut is LIKELY SAFE in food amounts. But there isn't enough information to know if it's safe in the larger amounts used as medicine. Stay on the safe side and stick to food amounts. Black walnut bark is POSSIBLY UNSAFE. Don't take black walnut bark by mouth or apply it to the skin. There isn't enough reliable information to know if black walnut leaf or shell is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.



Minor Interaction

Be watchful with this combination

  • Medications taken by mouth (Oral drugs) interacts with BLACK WALNUT

    Black walnut hulls contains a large amount of chemicals called tannins. Tannins absorb substances in the stomach and intestines. Taking black walnut along with medications taken by mouth can decrease how much medicine your body absorbs, and decrease the effectiveness of your medicine. To prevent this interaction, take black walnut at least one hour after medications you take by mouth.



The appropriate dose of black walnut depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for black walnut. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

View References


  • Amarowicz, R., Dykes, G. A., and Pegg, R. B. Antibacterial activity of tannin constituents from Phaseolus vulgaris, Fagoypyrum esculentum, Corylus avellana and Juglans nigra. Fitoterapia 2008;79(3):217-219. View abstract.
  • Bhargava, U. C. and Westfall, B. A. Antitumor activity of Juglans niga (black walnut) extractives. J Pharm.Sci. 1968;57(10):1674-1677. View abstract.
  • Blikslager, A. T., Yin, C., Cochran, A. M., Wooten, J. G., Pettigrew, A., and Belknap, J. K. Cyclooxygenase expression in the early stages of equine laminitis: a cytologic study. J Vet.Intern.Med. 2006;20(5):1191-1196. View abstract.
  • Eaton, S. A., Allen, D., Eades, S. C., and Schneider, D. A. Digital Starling forces and hemodynamics during early laminitis induced by an aqueous extract of black walnut (Juglans nigra) in horses. Am.J Vet.Res. 1995;56(10):1338-1344. View abstract.
  • Fontaine, G. L., Belknap, J. K., Allen, D., Moore, J. N., and Kroll, D. L. Expression of interleukin-1beta in the digital laminae of horses in the prodromal stage of experimentally induced laminitis. Am.J Vet.Res. 2001;62(5):714-720. View abstract.
  • Hurley, D. J., Parks, R. J., Reber, A. J., Donovan, D. C., Okinaga, T., Vandenplas, M. L., Peroni, J. F., and Moore, J. N. Dynamic changes in circulating leukocytes during the induction of equine laminitis with black walnut extract. Vet.Immunol.Immunopathol. 4-15-2006;110(3-4):195-206. View abstract.
  • Loftus, J. P., Belknap, J. K., and Black, S. J. Matrix metalloproteinase-9 in laminae of black walnut extract treated horses correlates with neutrophil abundance. Vet.Immunol.Immunopathol. 10-15-2006;113(3-4):267-276. View abstract.
  • Montoya, J., Varela-Ramirez, A., Estrada, A., Martinez, L. E., Garza, K., and Aguilera, R. J. A fluorescence-based rapid screening assay for cytotoxic compounds. Biochem Biophys.Res.Commun. 12-24-2004;325(4):1517-1523. View abstract.
  • Moodley, R., Kindness, A., and Jonnalagadda, S. B. Elemental composition and chemical characteristics of five edible nuts (almond, Brazil, pecan, macadamia and walnut) consumed in Southern Africa. J Environ.Sci.Health B 2007;42(5):585-591. View abstract.
  • Qasem, JR. Weed Allelopathy, Its Ecological Impacts and Future Prospects: A Review. Journal of Crop Production. 2001;4(2):43-119.
  • Riggs, L. M., Franck, T., Moore, J. N., Krunkosky, T. M., Hurley, D. J., Peroni, J. F., de la, Rebiere G., and Serteyn, D. A. Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract. Am.J Vet.Res. 2007;68(1):81-86. View abstract.
  • Waguespack, R. W., Cochran, A., and Belknap, J. K. Expression of the cyclooxygenase isoforms in the prodromal stage of black walnut-induced laminitis in horses. Am.J Vet.Res. 2004;65(12):1724-1729. View abstract.
  • Woeste, K., Burns, R., Rhodes, O., and Michler, C. Thirty polymorphic nuclear microsatellite loci from black walnut. J Hered. 2002;93(1):58-60. View abstract.
  • FDA. Qualified Health Claims: Letter of Enforcement Discretion - Walnuts and Coronary Heart Disease (Docket No 02P-0292). March 2004. Available at: Accessed on March 9, 2020.
  • Feldman EB. The scientific evidence for a beneficial health relationship between walnuts and coronary heart disease. J Nutr 2002;132:1062S-101S. View abstract.
  • Hu FB, Stampfer MJ. Nut consumption and risk of coronary heart disease: a review of epidemiologic evidence. Curr Atheroscler Rep 1999;1:204-9. View abstract.
  • Inbaraj JJ, Chignell CF. Cytotoxic action of juglone and plumbagin: a mechanistic study using HaCaT keratinocytes. Chem Res Toxicol 2004;17:55-62. View abstract.

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CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

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