A DECADE OF psychiatric treatment has been marked by the advent and increased usage of numerous psychopharmacological agents. Throughout this period the search has continued to aid in the development of effective agents which have minimal side effects. Thioridazine hydrochoride (Mellaril) has received wide acceptance as an effective phenothiazine with a relatively low incidence of side effects.1 However, there have been sporadic reports2-6 during the past three years of an unusual side effect occurring in male patients taking thioridazine hydrochloride. The capacity for sexual excitation, with concomitant erection and orgasm, was intact, but without apparent evidence of ejaculation and emission of semen. This side effect has not been reported in normal subjects, and it was not observed in the author's experience with six normal males taking thioridazine hydrochloride.7 (This is not a statistically significant absence.) It has not been reported for other phenothiazines, but it has been