Halogenated phenol derivative.It has been used as a skin disinfectant, including for nipple-areola (West 1975), vaginal disinfectant (Strickland 1983) and in dental preparations for cavity treatment. As it is highly liposoluble it has high skin absorption, even through intact skin, both in infants and adults (Bye 1975), and its repeated use can cause elevated plasma levels (Tyrala 1977, Nal-BMJ 1972) that cause neurotoxicity (Evangelista 1996) and serious risk to life. It is very toxic when taken orally and can result in death (Mullick 1973, Nal-BMJ 1972). Between 1950 and 1980, it was used as a cutaneous disinfectant in neonates admitted to neonatal units to prevent infections from staphylococcus aureus (Tyrala 1977, Baber 1967) and in umbilical cord treatment, which led to deaths due to spongiform encephalomyelopathy (Martin 1982, Anderson 1981, West 1981).There have also been fatalities in older children where it was used as a disinfectant in burns and other skin conditions (Chilcote 1977, Mullick 1973). Since the late 1970s, it has been gradually replaced by other disinfectants (Hnatko 1977), although surprisingly its use persisted for years in many hospitals (Malhotra 1986, Martin 1982) with more than one tragic result (Martin 1982).There are restrictions on its sale, ranging, according to the country, from their total ban to limiting its concentration to less than 1% in disinfectants, soaps and cosmetics. Since the last update there has been limited published data on its excretion in breast milk. Its liposolubility makes it very likely that it will pass into breast milk in amounts that could be significant. The use of hexachlorophene to clean the nipple between feeds resulted in milk levels, although low, between 2 and 9 nanograms/ml (West 1975). Its use as powder for umbilical cord treatment doubled plasma levels at 8th day of life relative to birth (Gillespie 1974). The small dose of hexachlorophene in dental products may be low risk, but in many countries hexachlorophene has been replaced by other phenolic disinfectants (thymol, parachlorophenol). The American Academy of Pediatrics (AAP 2001) and experts (Hale 2017, p.449) find it inappropriate to use hexachlorophene during breastfeeding. Due to its rapid absorption, it should not be used on mucous membranes or damaged skin, much less on the chest.