BACKGROUND Striae, or stretch marks, are very common skin disorders that do not impair bodily function, but are of considerable cosmetic concern to many patients. Traditionally, treatment options have been very limited. This study examines the results of treating striae using the 585-nm pulsed dye laser. Stimulation of a variety of wound healing processes has been attributed to low energy laser therapy. Clinically, improvement of hypertrophic and erythematous scars with the 585-nm pulsed dye laser at energy densities of 6-7 J/cm2 is well established. Since striae are dermal scars, evaluation of this same therapy to treat striae was undertaken. OBJECTIVE To evaluate the effectiveness of the 585-nm flashlamp-pumped pulse dye laser in treating cutaneous striae. METHODS Thirty-nine striae were treated with four treatment protocols. These treated striae were compared with untreated striae controls in the same patient. The patients ages ranged from 23 to 52 years, with an average age of 36 years. The average age of the treated striae prior to initial treatment was 14 years (range, 8 months to 32 years). Treatment parameters included spot sizes of 7 and 10 mm and fluences of 2.0, 2.5, 3.0, and 4.0 J/cm2. Response to therapy was evaluated through clinical grading, sequential photography, and optical profilometry at a blinded laboratory. Skin biopsies were also examined with light microscopy from two of the 39 striae that were treated. RESULTS Subjectively, striae appeared to return toward the appearance of normal skin with all protocols. However, the protocol with 10-mm spot size using 3.0 J/cm2 fluence improved the appearance of striae better than the other treatment protocols. Objectively, shadow profilometry revealed that all treatment protocols reduced skin shadowing in striae. This result corresponds with surface patterns of striae returning to that closely resembling adjacent normal skin surface patterns. Histologically, using hematoxylin and eosin stains as well as elastin strains, striae treated with a low fluence pulsed dye laser treatment protocol regained normal appearing elastin content when compared with normal (non-striae) skin adjacent to the treated striae. CONCLUSIONS Treatment with the 585-nm pulsed dye laser at low energy densities was shown to improve the appearance of striae. Apparent increased dermal elastin was also observed 8 weeks posttherapy and possibly contributed to the improvement seen in the study patients.