Abstract: A pharmaceutical or cosmetic composition for topical application comprises, in a physiologically acceptable support, the combination of benzoyl peroxide and at least one quaternary ammonium lipophilic salicylate having general formula (I): ##STR1## where: (i) R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be identical or different, representing a substituted or interrupted alkyl or cycloalkyl radical;(ii) R.sub.3 and/or R.sub.4 represent(s) the group:R.sub.8 --OC.sub.2 H.sub.3 R.sub.7 ].sub.n [OCH.sub.2 CHOH--CH.sub.2 ].sub.pwhere O.ltoreq.n.ltoreq.4 and p is 0 or 1; R.sub.8 represents H or an alkyl, alkenyl, alkylcycloalkyl or alkylanyl radical;(iii) R.sub.4 represents an alkylenephenyl radical;(iv), (v): R.sub.1 and R.sub.2 may form an aromatic or nonaromatic saturated or unsaturated heterocycle;(vi) R.sub.1, R.sub.2 and R.sub.3 together with nitrogen, may form polycyclic derivatives; and R.sub.5 represents a group having the formula: ##STR2## where n may vary from 0 to 10.

Abstract: A pharmaceutical and cosmetic composition for topical application comprises in a physiologically acceptable medium a combination of benzoyl peroxide and a quaternary ammonium salt selected from a quaternary ammonium alkyl sulfate of sulfonate, an aryl sulfonate and an alkyl aryl sulfonate.