This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Walnut Leaves, Juglans regia. Official in Austria, Belgium, Germany, Mexico, Spain, and Switzerland. This is the English or European walnut, and the leaves possess astringent properties availed of in the treatment of various external conditions.
Butternut, Juglans cinerea, is an American species not official. A good fl. made from the bark of the root is one of the most satisfactory laxatives for use in chronic constipation. The action is similar to that of rhubarb. Give 5- to 20-minim doses. I have found juglans one of the least objectionable of laxatives, gentle in action but prolonged in influence.
In doses short of actual purgation, juglans is an eliminative agent of value as a "system cleanser" in autointoxication and the "dirty skin" so commonly incident thereto. Juglans is a native remedy which should be more extensively used.