a toxic substance, C11H6O3, found in certain plants, including parsnips, used to increase the response to ultraviolet light in the treatment of severe cases of acne and psoriasis.
Origin: 1930–35; < Neo-Latin Psoral(ea) name of a genus of plants yielding the compound (< Greek psōraléa, neuter plural of psōraléos mangy, in reference to the glandular dots on the plant; see psoriasis) + -en, variant of -ene
psoralen pso·ra·len (sôr'ə-lən) n. Any of a group of chemical compounds found naturally in certain plants that are used in the treatment of psoriasis and vitiligo.