PSORALEN /SAW.ruh.len/ n. a naturally occurring chemical used to treat skin conditions
Psoralen occurs naturally in several common plants, including parsnips, figs, parsley and celery. It is mainly used to treat skin conditions such as acne, PSORIASIS, EKZEMA, and VITILIGO (that’s the skin pigmentation disease Michael Jackson had).
The chemical works because of its tendency to increase the skin’s ability to absorb light, which then does the actual healing. Unfortunately, this property of psoralen also leads to an increased chance of developing skin cancer, which prompted its ban from being used in sun tanning products in the mid 1990s.