CAUTION: Don’t scratch! Scratching spreads the poison.
As soon as possible, wash the skin thoroughly with household soap and plenty of water. Scrub the skin well. Wash the contaminated clothes and shoes or you could be re-affected with poison ivy again even after it has dried.
Crushed leaves of Jewelweed are poulticed on recent poison ivy rash — a well known folk remedy. Also the mucilaginous stem juice can be applied to the rash.
Lobelia is also good for poison ivy irritation.
Other remedies include squeezing the juice of Aloe Vera leaf onto the affected area, or bathe it with cider vinegar.