Health Guide

Black walnut

What is it?

Black Walnut is an herbal medicine that has been used for chronic stomach upset and topical (on the skin) fungal infections. It has also been used for worms, parasites, eczema, and as a treatment for poison oak rashes.

Other names for Black Walnut include: Juglans nigra, Junglans regia, English Walnut Leaf, Walnut Hull, European Walnut Leaf, and Persian Walnut Leaf.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have any other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much Black Walnut you should take. The amount depends on the strength of the medicine and the reason you are taking Black Walnut. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.


  • Before taking Black Walnut, tell your doctor if you are pregnant or breastfeeding
  • If you have liver disease, you should not take Black Walnut
  • Repeated application of Black Walnut to the skin is not advised due to the risk of developing skin tumors
  • Black Walnut should not be used for long periods of time (5)

Side Effects:

Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

  • Breathing problems or tightness in your throat or chest
  • Chest pain
  • Skin hives, rash, or itchy or swollen skin

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

  • Skin rash caused by putting Black Walnut on your skin (3,4)
  • Skin tumors may occur after many applications of Black Walnut to the skin (5)


1. Weiss RF: Herbal Medicine. Beaconsfield Publishers LTD, Beaconsfield, England; 1988.

2. Blumenthal M, Goldberg A & Brinckmann J: Herbal Medicine: Expanded Commission E Monographs. The American Botanical Council, Austin, TX; 2000.

3. Craton D and Williams R: Juglone dermatitis: allergy or irritant? Indiana Academy of Science 1980; 90: 98-102.

4. Siegel J: Dermatitis due to black walnut juice. AMA Archives of Dermatology and Syphilology 1954; 70(4):511-513.

5. McGuffin M, Hobbs C, Upton R et al: American Herbal Products Association's Botanical Safety Handbook. CRC Press, Boca Raton, FL; 1997.

6. Clark A, Jurgens T & Hofford C: Antimicrobial activity of juglone. Phytotherapy Research 1990; 4(1): 11-14.

Last Updated: 7/4/2018
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

All rights reserved