The green hulls are the most sought-after for their medicinal and astringent qualities. Black walnut (Juglans nigra) is a powerful astringent and anthelmintic botanical. It helps expel intestinal worms, with a species-specific effectiveness for ringworm (Tinea corporis). Black walnut green hulls also eliminate parasites from extracellular fluids which include blood and lymph. The liver, kidneys, brain, and heart can also benefit from their antiparasitic action. Black walnut contains flavonoids; tannins; ellagic, tannic, and gallic acids; juglones; trace minerals; and vitamins. Black walnut hulls also exert a cleansing and purifying effect on the blood; however, their main therapeutic use is to combat and expel intestinal parasites from their host, which could be you.