['Current treatments for acne scars and enlarged facial pores have shown limited efficacy.', 'To evaluate the efficacy and safety of the fractional photothermolysis system (FPS) with dynamic operating mode on acne scars and enlarged pores.', 'Twelve patients with mild to moderate atrophic acne scars and enlarged pores were included in this study. Three sessions of FPS treatment were performed for acne scars and facial pores monthly. Two blinded dermatologists who compared before and after photos based on a quartile grading scale conducted objective clinical assessments of acne scar- and facial pore-treated areas. We took a biopsy immediately after one treatment with the laser from one of the authors to assess the histologic effects of the laser on facial pores.', 'Follow-up results at 4 months after the last treatment revealed that, of the 12 patients, for acne scars, five demonstrated clinical improvements of 51% to 75% and three demonstrated improvements of 76% to 100%, and for facial pores, five demonstrated moderate clinical improvements of 26% to 50% and three demonstrated improvements of 76% to 100%. Side effects, including pain, post-treatment erythema, and edema, were resolved within 1 week.'] Does efficacy of the fractional photothermolysis system with dynamic operating mode on acne scars and enlarged facial pore?