Phenylmercuric borate is classified as antimicrobial preservative. It is bactericidal against many Gram-positive and Gram-negative species. Fungicidal activity has been demonstrated against Candida albicans and Aspergillus niger. Phenylmercuric borate (PHB) is very rapidly incorporated into the cells of Escherichia coli. On the membrane, an important part of PHB seems to be associated with the ribosomes and particularly to the ribosomal proteins. Phenylmercuric borate solution is indicated for the treatment of tonsillitis, otitis, vulvovaginitis, furuncles, anthrax and ulcers, pyoderma, impetus, gingivitis and stomatitis. The regular hand disinfection with a liquid soap containing phenylmercuric borate enhanced urinary excretion of mercury indicating an increase in total daily absorption of the toxic metal. The additional amounts of mercury absorbed through the use of mercury contained in skin disinfectants are potentially dangerous for human.