EPIDUO is used to treat acne. It is used on the face, chest or back. It combines two active ingredients, adapalene and benzoyl peroxide which work through different but complementary ways. Adapalene is a topical retinoid. Its main actions are to normalise skin cell development, prevent pores from being blocked and promote skin renewal. Benzoyl peroxide kills bacteria (antibacterial) and also works by softening and peeling the outer layer of the skin. Adapalene and benzoyl peroxide work together to rapidly reduce inflammation.