Microscope image by e-pyton from Fotolia.com

Juglans nigra, known as black walnut, is a hardwood tree that grows naturally in North America and some European countries. The tree produces edible fruits that are also called black walnut, and contain protein, essential fatty acids and minerals. Black walnut extracts usually are derived from the outermost hull, and they are available in liquid, capsules and tablets. Some herbalists believe that a black walnut tincture, which is an alcohol extract, is the most effective preparation, according to the American Cancer Society, or ACS. Consult a qualified health care provider before taking black walnut hull tincture for any medical condition.

Claimed Anti-Parasitic Benefits

Black walnut hull is purported to kill more than 100 types of parasites and to eradicate them from the digestive tract. Proponents of black walnut as an herbal remedy recommend the substance for travelers to areas with contaminated water supplies. Evidence does not indicate that black walnut hulls are effective for eradicating intestinal parasites, according to the ACS. Another recommendation involves combining black walnut hull tincture with wormwood and cloves to eliminate roundworms and other intestinal parasites, according to the University of Maryland Medical Center, or UMMC. Commercial products are available that include these three components. Pregnant women should not take wormwood, and it may not be safe for people with ulcers.

Claimed Disease Cure

A small number of alternative medicine practitioners claim parasite cleansing is a cure for cancer and HIV because they believe an intestinal fluke causes these diseases, according to the ACS. The black walnut, wormwood and clove tincture is purported to kill this parasite without significant side effects. Evidence does not indicate that black walnut hulls are effective for curing or preventing any disease, cautions the ACS.

Antitumor Effects

Laboratory studies show that a chemical compound in black walnut called juglone may decrease the risk of cancer and may have antitumor effects, according to the ACS. For instance, a study published in the October 6, 2009 issue of "Experimental and Toxicologic Pathology" investigated the action of juglone in causing human gastric cancer cells to self-destruct. The ACS cautions that no studies are available to confirm this effect in humans.

Traditional Uses

Black walnut hull has many other traditional uses, although no research is available to support these purposes, as noted by the ACS. It is promoted as an herbal remedy for sore throats and tonsillitis, and for relieving minor digestive ailments. Some herbalists also use black walnut topically to treat acne, eczema, ringworm and skin irritation.