Euell Gibbons, and his book, Stalking the Wild Asparagus, explains how to use poison ivy leaves to build an immunity to poison ivy.
also,
The most well known herbal treatment for poison ivy is the juice of jewelweed (Impatiens spp.) There may be a compound in jewelweed which binds to the
same sites as the urushiol metabolites, thereby blocking their access. If this is true, applying jewelweed to the skin just before or just after
exposure should prevent the rash. There is quite a lot of anecdotal evidence that this works. Jewelweed also has anti-inflammatory properties and
should be a soothing treatment for an already developed rash.
Plantain (Plantago spp.), applied as a poultice, may also prevent the rash and will also soothe an already developed rash. Other plants with
astringent and/or soothing properties may also help.
There is anecdotal evidence of people desensitizing themselves to poison ivy by eating poison ivy leaves, first starting with a tiny amount and
then gradually increasing the dosage until a maintenance level is reached. The most common side effect of this treatment, however, is getting the rash
where the urushiol passes out of your body. It is also possible to have symptoms internally. Similar treatments in pill form can be obtained from a
doctor or dermatologist, but have the same unpleasant side effects. No other immunization appears to be available at this time.
Medicinally, poison ivy has been used to treat paralysis, arthritis, and certain persistent skin disorders, and also as a sedative. It is still
used in homeopathic medicine for arthritis and skin disorders.
from here:
www.kingdomplantae.net...