The hygiene definition specifies standards for handwashing and menstrual hygiene management facilities. Hygiene is essential to the public health mission of reducing the transmission and consequences of disease. The two leading causes of childhood mortality worldwide are diarrheal disease and acute respiratory infections, accounting for two-thirds of the deaths of children under age five. Both of these categories of illness are closely associated with inadequate hygiene. In addition, chronic parasitic infections and diarrhea can lead to anemia, which further hinders children’s development. The provision of safe water and sanitation, and improved hygienic behaviors more generally, has the potential to alleviate the proximate causes of these illnesses and thereby improve health.

Medical evidence suggests that the hands are the main transmitters of diarrhea and respiratory infections. As such, they constitute disease vectors carrying respiratory microorganisms and fecal material into the domestic environment of the susceptible child. Health experts recommend handwashing with soap as a critical action in protecting public health because it is a mainstay in infection control. Yet, rates of handwashing with soap at critical times remain low throughout the world, even when both soap and water are available.

• Handwashing with soap at the right time - before eating or making food and after the toilet - can reduce the risk of diarrhoea, the second biggest killer of children under 5, by around 40%.
• In a sample of developing countries, the observed rates of handwashing with soap range between 0 and 34 percent after defecation and 3 and 37 percent after cleaning up a child.
• Handwashing event without water (in sand, for example), also significantly reduces the likelihood of diarrhea, emphasizing the importance of hygiene in improving health.
• According to the United Nations and UNICEF, one in five girls of primary-school age are not in school, compared to one in six boys. The installation of toilets and latrines may enable school children, especially menstruating girls, to further their education by remaining in the school system.

>> Access to a selection of UN publications on Hygiene