Evidence supporting the use of: Black walnut
For the health condition: Insect Repellant

Links: Go back one page, Tool main page, Ingredients list, Health conditions list, Body systems list

Synopsis

Source of validity: Traditional
Rating (out of 5): 2

Black walnut (Juglans nigra) has a long history of traditional use as an insect repellent, particularly in North American folk medicine. Indigenous peoples and early settlers used various parts of the black walnut tree, especially the hulls, to deter insects such as fleas, mosquitoes, and lice. The main compound believed to be responsible for its insect-repelling properties is juglone, a natural chemical found in the leaves, roots, and husks. Juglone is known to be toxic to many insect species and even to certain plants, which is why black walnut trees inhibit the growth of some nearby vegetation (allelopathy).

Despite this traditional use, scientific studies directly supporting the efficacy of black walnut as an insect repellent in humans are limited. Laboratory studies have demonstrated that juglone and other compounds from black walnut can have insecticidal properties, but there is a lack of robust clinical trials or field studies confirming its safety and effectiveness for topical use against insects. Most evidence remains anecdotal or based on in vitro research. Therefore, while black walnut’s use as an insect repellent has a traditional foundation and some preliminary scientific rationale, it is not widely endorsed in modern evidence-based guidelines for insect bite prevention.

More about black walnut
More about Insect Repellant