In acne medication, what's the difference between salicylic acid & benzoyl peroxide?

Clearing pores. Benzoyl peroxide is a drying agent that kills the bacteria causing acne. Salicylic acid removes dead skin, unclogs pores, and kills the bacteria. Salicylic acid is more effective than benzoyl peroxide in clearing the pores. It also has less side-effects that benzoyl peroxide.
Two chemicals.... ...That both help acne, but are entirely unrelated in their structure. Benzoyl peroxide is usually applied as a cream, like in clearasil (benzoyl peroxide). Salicylic is often an ingredient in acne washes, and can also be used by itself as a peeling agent. Both are effective.