This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Pharm. Land. Nux juglans C. B. Juglans regia Linn. Walnut: a large tree commonly cultivated in this and most other countries of Europe for its fruit, which is a fleshy drupe, becoming husky when ripe, and inclosing a nut with an edible kernel. The unripe fruit (which is the part specifled in the London catalogue) has a sharp acerb taste, and when handled, tinges the skin with rufl:-coloured durable spots. Insused in water it imparts a bitter harsh taste to the fluid, which becomes blackish on the addition of vitriol of iron. An extract prepared from it is subfaline, lightly acerb and styptic, and sussiciently grateful to the smell. This extract is accounted an excellent anthelmintic, given twice or thrice a day in the dose of a tea spoonful to children. It proves purgative, and expels the worms with the stools. A syrup made with a strong decoction of green walnuts and brown sugar, is much used in some parts of England as a domestic aperient medicine. The outer covering and shell of the fruit have been joined with guaia-cum and sarsaparilla as ingredients for fudorific decoctions in rheumatic and venereal cases. Green walnuts enter an antivenereal decoction, the formula of which is given in a Treatise on the Venereal Disease by Dr. Swediaur, edition second and third. This decoction is by some supposed to be the genuine Lisbon diet drink which has acquired considerable reputation among the nostrums for this malady.
The culinary use of unripe walnuts as a pickle is well known