Xanthotoxin (Methoxsalen ) is a potent tricyclic furocoumarin suicide inhibitor of CYP (cytochrome P-450), is an agent used to treat psoriasis, eczema, vitiligo and some cutaneous Lymphomas in conjunction with exposing the skin to sunlight. Xanthotoxin has anticonvulsant activities, it can protect the animals against maximal electroshock-induced seizures; Xanthotoxin prevents bone loss in ovariectomized mice through the inhibition of RANKL-induced osteoclastogenesis, it may be considered to be a new therapeutic candidate for treating osteoporosis. Methoxsalen is a member of the class of psoralens that is 7H-furo[3,2-g]chromen-7-one in which the 9 position is substituted by a methoxy group. It is a constituent of the fruits of Ammi majus. Like other psoralens, trioxsalen causes photosensitization of the skin. It is administered topically or orally in conjunction with UV-A for phototherapy treatment of vitiligo and severe psoriasis.