Juglans nigra, more commonly known as black walnut, is a deciduous tree producing nuts rich in protein, essential fatty acids and fiber. People also take black walnut as an herbal remedy, typically using an extract from the sticky contents of the outermost hull, according to Drugs.com. Black walnut extract is used topically for treating eczema, psoriasis and warts, and internally for eliminating parasites. Some alternative practitioners theorize black walnut may be an effective cancer treatment, particularly those who consider parasites to be a cause of this illness. Evidence does not support the idea that black walnut hulls eliminate parasites or treat any disease, according to the American Cancer Society. The most likely side effect is an allergic reaction.
Nut allergies are common in the United States, as explained by Drugs.com, with about 1 percent of people allergic to some type of tree nuts or to peanuts. Peanuts are technically legumes and not true nuts. If you are allergic to walnuts or to any other nuts, especially pecans, you may have a negative reaction to black walnut extract. Signs of an allergic reaction to black walnut as listed by PDR Health may include skin itching or swelling, a rash or hives, breathing difficulty, tightness in the chest or throat and chest pain. An allergic reaction to black walnut extract should be considered a medical emergency. Peanuts and walnuts are the most likely nuts to cause a life-threatening anaphylactic reaction, according to Drugs.com. This shock reaction involves a sudden drop in blood pressure and extreme difficulty breathing.
Topical Side Effects
Using black walnut extract topically can cause a skin rash, and the substance has cytotoxic properties, or a destructive effect on cells, as noted by Drugs.com. PDR Health advises against regular topical use because skin tumors may develop.
Pregnant women should not consume black walnut extract or apply it topically. Black walnut components can change the developing baby's genetic material, as explained by Drugs.com, and negative effects have been reported.