Great question. Both benzoyl peroxide and salicylic acid are cleared by the FDA for acne treatment. Benzoyl peroxide is the most effective (prescription and OTC) anti-acne ingredient out there. It is a very effective anti-bacterial agent with some exfoliating properties to unclog the obstructed skin pores. Salicylic acid is a milder anti-acne agent. It fits people with more sensitive skin, people that have primarily comedones (blackheads and whiteheads) and women with adult acne. Its main effect is to unclog skin pores, prevent blackheads and whiteheads and has some anti-inflammatory effects. Both products should be used at night. The application is the same - a small amount of the cream spread evenly on the whole face. To prevent over dryness, do not apply the products around the eyes and on the skin folds (sides of the nose and the mouth). In the morning, you need to apply an oil-free moisturizer or sunscreen to further reduce skin dryness and protect form the sun.