Black Walnut Oil's Effect on Worms


Black walnut is a hardwood tree also know as American walnut. They grow primarily through the central and eastern parts of the United States.The tree has been used extensively for logging due to its smooth fine grained wood. Groves have been reduced across the United States limiting commercial use to veneers and oils as of 2010. The nuts of the trees are an important dietary product which is marketed to bakeries, confectioners and specialty super markets.The shells of the walnut are used in oil well drilling and industrial cleaning. The leaves and bark have been used natively to treat a variety of physical complaints.

Black Walnut Features

Black walnuts are large trees growing to around 150 feet tall. The canopy is rounded and the growth habit is straight with a five foot diameter trunk. The leaves present a lacy appearance and are pinnate with leaflets up to three inches long. They are yellowish green with fine hairs on the underside and turn a bright yellow in fall before they drop. The trees self pollinate with flowers appearing in late Spring. Seeds ripen in October and grow up to two inches in diameter. Nuts will fall when ripe although some clusters will remain on the tree. The nuts are the most important commercial product from the American walnut tree, used both for the nutmeats, but also as an abrasive from ground shells and oils for cooking and natural therapies.

Oil Harvest

Walnuts are approximately half oil. The traditional way to extract the oil was to grind the nutmeats very finely into a paste and then roasted. A hydraulic press was then used to squeeze out the oil. Impurities were filtered out and the result was a topaz colored flavorful oil. Cold pressed oil is considered a superior oil and the process needs to roasting. The nutmeats are pressed using a continuous screw press method that releases less oil but is said to be of better flavor. The oil is stored in drums until the solids settle to the bottom. Walnut oil is more perishable than other oils and can get rancid if not stored in a cool dark area and used fairly promptly.


The worms that most often affect animals and humans are intestinal worms. These would be round worms, pinworms and tapeworms. Some of these worms can get up to a meter in length and live in the digestive tract. The worms can cause infection and the most common roundworm diagnosed, Ascariasis, is carried by one billion people worldwide. The worms usually are contracted by contact with earth and then oral contact or they can burrow into the skin. Side effects can be very severe including vomiting and diarrhea, blood in the stool and weight loss. Risk factors are living in a warm and humid environment, minimal sanitation and malnutrition. These conditions are generally found in economically depressed areas of the world where cheap natural medicines are the easiest to get people to take and dispense. Black walnut oil is a useful anti-parasitic.

Black Walnut Oil as an Anti-Parasitic

The black walnut tree contains a compound called juglone in the nuts. The name is derived from the botanical name, Juglans. The juglone is also in the European nuts indicating that medicinal properties would be the same. The bark and shell have numerous curative properties and the oil is a gentle laxative and intestinal cleanser. It has been used for a very long time, and Native Americans have used it as a vermifuge to eliminate tapeworms. The oil from the green unripe nuts is said to be good for intestinal parasites including roundworms. Practical Farmers of America and Iowa State University compiled a list of parasite remedies for use in swine and included the black walnut. The University of Maryland Medical Center recommends it for use in humans.

How it Works

There is still speculation as to the verity of black walnut oil in parasitic application and studies are ongoing as of 2010. However, the oil is referenced in Native American healing lore and traditional European curatives. The juglone is contained in all parts of the plant but concentrated more heavily in the hull. It is produced by the tree to repel competitors from growing around it. The chemical is a phytotoxic allelochemical meaning it kills plants. It is believed to also control fungus and yeast. Black walnuts also contain tannins, which in high concentrations are a useful antithelminic (worm killer) and a defense mechanism the plant produces to protect it against biological and parasitic infestation.

Keywords: Black walnut oil, Walnut curative properties, Black walnut parasitic

About this Author

Bonnie Grant began writing professionally in 1990. She has been published on Web sites like GardenGuide and eHow. Grant recently earned a Bachelor of Arts in business management with a hospitality focus from South Seattle Community College.