Black walnut shells are one of the oldest and most traditional remedies for killing intestinal parasites in western herbal medicine. Some people take walnut extracts, made from the unripe green shells, to promote digestion, stimulate liver function and remove parasitic organisms. Black walnut may not be safe for everyone, however, so talk with your doctor before using black walnut products.
History
Black walnut shells have been used as a medicine for digestive problems and parasite infections for hundreds of years. Herbalist Dr. Nicholas Culpeper, author of "Culpeper's Complete Herbal," recommended green walnut shells for earache, inflammation, sore mouth, colic and weak digestion and recommended the leaves for killing what he called stomach broad worms. Native Americans used black walnuts as a laxative, dye and food and chewed the shells for relief from colic. According to a study published in 2007 in Veterinary Parisitology, researchers at the University of Victoria in Canada found that use of black of walnut to kill parasites in livestock is widespread throughout British Columbia.
Laboratory Research
In a study published in 2005 in The Journal of Biological Chemistry, researchers at the University of Dundee in Great Britain tested the actions of juglone, the active compound in black walnut, on toxoplasma gondii parasites in vitro. Juglone had a significant effect on the parasites, inhibiting their growth while not harming the host cells. Researchers said that juglone creates oxidative free radicals, which destroy the parasites. Toxoplasma gondii are particularly susceptible to oxidative damage, so juglone may be a specific herbal treatment for this parasite.
Animal Research
The use of black walnut shells in treating animals with parasites may give clues to its action in humans. In a study published in 2000 in the Russian medical journal Meditsinskaia Parazitologiia, researchers investigated the effects of a walnut extract on animals with parasitic infections. Although the walnut extract extract was not identified specifically as black walnut, it showed significant actions on the tested animals. The walnut extract was 100 percent effective in eliminating cyphaciasis parasites in mice, and at a higher doses it was 100 percent effective in eliminating ascariasis and heterakiasis parasites in chickens. These results are very promising and support the traditional use of black walnut as an anthelmintic. More research is required to confirm results in humans.
Safety and Toxicity
Black walnut has caused adverse reactions and side effects in some people, according to the website Drug Information Online. The active chemical in the fruit and shells, juglone, is potentially toxic and when it's used topically, it may cause dermatitis and some types of skin cancer. Black walnut flowers are a common air allergen. Eating walnuts can also trigger an allergic reaction. Consult with a registered medical herbalist and a doctor before using black walnut products to make sure they are OK for you to take.
References
- "Culpeper's Complete Herbal"; Dr Culpeper; 1998 reprint
- Veterinary Parisitology; Ethnoveterinary Medicines Used to Treat Endoparasites and Stomach Problems in Pigs and Pets in British Columbia, Canada; C. Lans, et al.; September 2007
- The Journal of Biological Chemistry; Functional Analysis of the Glutathione S-transferase 3 from Onchocerca volvulus (Ov-GST-3): A Parasite GST Confers Increased Resistance to Oxidative Stress in Caenorhabditis elegans; A. Kampkotter, et al.; 2007
- Meditsinskaia Parazitologiia; A trial of the preparation Cheblin-SK-1 in models of nematodiases; A. Samylina, et al.; 2000
- Drug Information Online: Black Walnut
- Non-Timber Forest Products: Black Walnut
