This study will assess safety and efficacy of four treatments with methylaminolevulinate (MAL) at 80 mg/g performed with and without occlusion and followed by red light exposure 90 minutes later in subjects with facial acne vulgaris. Subjects will be randomized to one of two groups of 20 subjects: Group 1 will receive 25 J/cm2 of red light (45 mW/cm2) and group 2 will receive 37 J/cm2 of red light (90 mW/cm2). For each subject one side of the face will be randomized to receive MAL for 90 minutes without occlusion and the other side of the face will receive MAL for 90 minutes with occlusion.