BACKGROUND Post-inflammatory erythema (PIE) and post-inflammatory hyperpigmentation (PIH) are the most common acne-related sequelae with no effective treatments. By combining different cut-off filters, intense pulsed light (IPL) therapy can effectively treat these conditions with few side effects. While the safety and effectiveness of IPL for treating post-burn hyperpigmentation is well known, there is little evidence for its benefits for acne-related PIH. In this article, we evaluate the efficacy and safety of IPL for the treatment of acne-related PIE and PIH. METHODS This retrospective study evaluated 60 patients with more than 6 months of PIE and PIH treated by the same IPL device and similar protocols. The treatment included three to seven sessions at 4-6-week intervals, and three cut-off filters (640 nm, 590 nm and 560 nm) were used sequentially in each session. Using the Global Aesthetic Improvement Scale (GAIS), Cardiff Acne Disability Index (CADI), and Erythema Assessment Scale (EAS), patients were evaluated on the basis of their facial photographs. The facial brown spots and red areas were visualised and analysed using the VISIA-CR system. Six months after the last treatment, the patients were assessed for acne relapse or any side effects.Please check and confirm that the authors and their respective affiliations have been correctly processed and amend if necessary.Checked and confirmed. No further corrections. RESULTS On the basis of the GAIS, 49 of 60 patients (81.7%) showed complete or partial clearance of erythema and hyperpigmentation. The CADI and EAS scores showed significant improvement (p < 0.01) after IPL treatment compared with pre-treatment. A significant reduction (p < 0.01) in the facial brown spots and red areas was seen after IPL treatment. While no long-term side effects were reported, seven patients (11.7%) experienced acne relapse at follow-up. CONCLUSIONS IPL is an effective and safe treatment for acne-related PIE and PIH.