Azelaic acid (AzA; HOOC-(CH2)7-COOH) is a naturally occurring compound that interferes with acne pathogenesis by virtue of its antikeratinizing, antibacterial, and anti-inflammatory properties. Vehicle-controlled studies have verified that AzA exercises a significant and clinically relevant effect on both non-inflammatory and inflammatory acne lesions. In the treatment of moderate to severe acne, 20 percent AzA cream may be favorably combined with minocycline (90 percent good and excellent results), and may contribute towards reducing recurrences following discontinuation of systemic therapy (maintenance therapy with AzA cream). Particular advantages of AzA therapy include its favorable safety and side effect profile. It is non-teratogenic, is not associated with systemic adverse events or photodynamic reactions, exhibits excellent local tolerability, and does not induce resistance in Propionibacterium acnes. The 15 % azelaic acid gel has recently proven efficacy in a maintenance treatment of papulopustular rosacea after a combination treatment with oral doxycycline.