Claimed Herbal Treatment for Poison Oak

In the article on mugwort: "Many hikers and outdoor enthusiasts claim that rubbing this plant on skin exposed to poison oak prevents or lessens an outbreak or reaction to the poison oak, but this does not seem to be founded on any published data." I volunteer to do a sample size N=1 study next time I get poison oak, which is never far off. To be honest, I don't have high hopes, but the best proof is the proof that a skeptic can't ignore.