THE USE OF tranquilizing agents in the therapy of psychiatric patients has promoted considerable interest among investigators concerning the mechanism of action and the untoward reactions of these drugs. Many of the phenothiazine derivatives cause side effects, some of which are cutaneous in nature. It is also known that chlorpromazine hydrochloride may induce sun-sensitive reactions.1-3It is the purpose of this paper to report a photosensitive manifestation which differs from those previously reported. Report of Cases Case 1.— A 28-year-old white female was committed to the Anoka State Hospital on Sept 22, 1955, with a diagnosis of chronic schizophrenic reaction. The patient has been in good health except for a residual paresis on the left side following poliomyelitis in 1955. Since May, 1963, she has noted a progressive pigmentation of the facial region, which is most prominent over the bulbous portion of the nose. The discoloration is most marked