OBJECTIVE: Our purpose was to determine the feasibility of selective photosensitization of vulvar condylomas by use of topical application of 5-aminolevulinic acid. STUDY DESIGN: In vivo fluorescence was assessed and biopsy specimens of condylomas were taken for fluorescence microscopy in 24 patients at different times after application of 2.5% 5-aminolevulinic acid ointment or 20% 5-aminolevulinic acid cream. RESULTS: Both in vivo fluorescence imaging and fluorescence microscopy showed selective fluorescence of condylomas of the labia minora and vestibule only within short time intervals, because fluorescence of poorly keratinized normal epithelium was induced by both 5-aminolevulinic acid formulations. In non-hair-bearing skin, lesional fluorescence remained highly selective. Fluorescence microscopy showed that 90 minutes after drug application peak selectivity in epithelial lesional fluorescence was significantly higher with 2.5% 5-aminolevulinic acid ointment (4.5 ± 0.9) than it was with 20% cream (2.1 ± 0.2). CONCLUSIONS: Selective fluorescence of vulvar condyloma acuminatum can be induced by nonselective topical 5-aminolevulinic acid application. Studies evaluating selective photodynamic destruction of condylomas are justified. (AM J OBSTET GYNECOL 1996;174:951-7.)