Injectable hyaluronic acid gel is a non-animal biomaterial used for soft tissue augmentation. The dermal implantation of this naturally occurring polysaccharide is reported to be well tolerated by patients, with a longer duration in tissue than bovine collagen without any major local or systemic side effects. We report a case of an acute hypersensitivity reaction in a woman after her third injection for improvement of melolabial fold wrinkles. An adverse granulomatous-like response to the intradermal injection of a modified hyaluronic acid gel is described. The patient developed indurated and erythematous papulocystic nodules in the melolabial folds bilaterally at the sites of injection. Injectable hyaluronic acid gel can be associated with severe allergic reactions and patients should be warned of this possible treatment side effect.