A stable, self-preserving, antimicrobial, composition suitable for the treatment of a variety of dermal as well as subcutaneous conditions. The compositions include as an active ingredient a quaternary ammonium compound, preferably benzethonium chloride, potentiated and synergized with menthyl lactate cooling agent in a cationic carrier. Optionally, a phenoxyethanol preservative and chlorhexidine digluconate antibacterial agent may be used to assist in enhancing the activity. The compositions kill a broad spectrum of gram-negative and gram-positive bacteria, fungus and yeasts. The compositions are used as first aid skin treatments and as skin sanitizers to help prevent bacterial contamination of minor cuts, scrapes and burns. The compositions are particularly useful when applied to the skin after hair removal in that they additionally cool, soothe and moisturize the skin. The compositions may also serve as a base vehicle in which additional skin care ingredients may be added to provide additional functionality to the compositions.