A recent large study evaluating nicotinamide for the treatment of acne or rosacea has confirmed the potential benefits of oral nicotinamide as an alternative approach to managing inflammatory lesions associated with acne vulgaris and acne rosacea. This article reviews the substantial number of reports published over the past 50 years that document the clinical utility and safety of oral and topical formulations of nicotinamide for the treatment of a variety of inflammatory skin conditions.