A widely used antiseptic (see ANTISEPTICS) which is active against a range of micro-organisms, including gram-positive and gram-negative organisms (see GRAM'S STAIN), Shigella dysenteriae, and Salmonella typhi. One of its advantages is that it retains its activity in the presence of soap, and is therefore often used in soaps and creams in a concentration of 1–2 per cent.