Hygiene refers to practices associated with ensuring good health and cleanliness. The scientific term "hygiene" refers to the maintenance of health and healthy living. The term appears in phrases such as personal hygiene, domestic hygiene, dental hygiene, and occupational hygiene and is frequently used in connection with public health. The term "hygiene" is derived from Hygieia, the Greek goddess of health, cleanliness and sanitation. Hygiene is also a science that deals with the promotion and preservation of health. Also called hygienics.

Personal hygiene

Washing the body and hair frequently.

Frequent washing of hands and face.

Oral hygiene—taking care of the teeth and gums, and treating or preventing bad breath

Daily brushing (with toothpaste) and flossing the teeth, to prevent tooth decay and gum disease. This also helps treat and prevent bad breath.

Chewing gum or rinsing mouth with antibacterial mouthwashes (such as Listerine) can also dispel bad breath

Cleaning of the clothes and living area.

Avoiding contact with bodily fluids, such as blood, feces, urine, and vomit.

Not touching animals before eating, or washing hands thoroughly between animal-touching and eating.

Holding a tissue over the mouth or using the upper arm/elbow region when coughing or sneezing, rather than a bare hand. Alternatively, washing hands afterwards.

Suppression of untidy habits, such as nose-picking, touching pimples, etc.

Not licking fingers before picking up sheets of paper or turning pages in a book. (Rubber fingertip covers and Glycerine-based products are available for this purpose, which are available from stationery stores, if one can find one.)

Not biting fingernails.

Wearing clean underwear and clothing daily.

Washing hands after using the toilet.

Not sharing towels, combs, hair brushes, and other personal things.

Changing bedsheets when a new person sleeps on the bed.

Food and cooking hygiene

: ''Main article: Food and cooking hygiene. See also Food safety.''

The purposes of food and cooking hygiene are to prevent food contamination, the transmission of disease, and to prevent food poisoning. Food and cooking hygiene protocols specify safe ways to handle and prepare food, and safe methods of serving and eating it. Such protocols include

Cleaning of food-preparation areas and equipment (for example using designated cutting boards for preparing raw meats and vegetables). (Cleaning may involve use of chlorine bleach for sterilization.)

Careful avoidance of meats contaminated by trichina worms, salmonella, and other pathogens; or thorough cooking of questionable meats.

Extreme care in preparing raw foods, such as sushi and sashimi.

Institutional dish sanitizing by washing with soap and clean water.

Washing of hands after touching uncooked food when preparing meals.

Not using the same utensils to prepare different foods.

Not sharing cutlery when eating.

Not licking fingers or hands while or after eating.

Not reusing serving utensils that have been licked.

Proper storage of food so as to prevent contamination by vermin.

Refrigeration of foods (and avoidance of specific foods in environments where refrigeration is or was not feasible).

Labeling food to indicate when it was produced (or, as food manufacturers prefer, to indicate its best before date).

Proper disposal of uneaten food and packaging.

Medical hygiene

Proper bandaging and dressing of injuries.

Use of protective clothing, such as masks, gowns, caps, eyewear and gloves.

Sterilization of instruments used in surgical procedures.

Safe disposal of medical waste.

Most of these practices were developed in the 19th century and were well established by the mid-20th century. Some procedures (such as disposal of medical waste) were tightened up as a result of late-20th century disease outbreaks, notably AIDS and Ebola.

History of hygienic practices

Elaborate codes of hygiene can be found in several Hindu texts such as the Manusmriti and the Vishnu Purana.http://www.sulabhtoiletmuseum.org/fact.htm Bathing is one of the five Nitya karmas (daily duties) in Sikhism, not performing which leads to sin according to some scriptures. These codes were based on the notion of ritual purity and were not informed by an understanding of the causes of diseases and their means of transmission. However, some of the ritual-purity codes did improve hygiene, from an epidemiological point of view, more or less by accident.

Regular bathing was a hallmark of Roman civilization.Elaborate baths were constructed in urban areas to serve the public, who typically demanded the infrastructure to maintain personal cleanliness. The complexes usually consisted of large, swimming pool-like baths, smaller cold and hot pools, saunas, and spa-like facilities where individuals could be depilated, oiled, and massaged. Water was constantly changed by an aqueduct-fed flow. Bathing outside of urban centers involved smaller, less elaborate bathing facilities, or simply the use of clean bodies of water. Roman cities also had large sewers, such as Rome's Cloaca Maxima, into which public and private latrines drained. Romans didn't have demand-flush toilets but did have some toilets with a continuous flow of water under them. (Similar toilets are seen in Acre Prison in the film ''Exodus.'')

Until the late 19th Century, only the elite in Western cities typically possessed indoor facilities for relieving bodily functions. The poorer majority used communal facilities built above cesspools in backyards and courtyards. This changed after Dr. John Snow discovered that cholera was transmitted by the fecal contamination of water. Though it took decades for his findings to gain wide acceptance, governments and sanitary reformers were eventually convinced of the health benefits of using sewers to keep human waste from contaminating water. This encouraged the widespread adoption of both the flush toilet and the moral imperative that bathrooms should be indoors and as private as possible.''Poop Culture: How America is Shaped by its Grossest National Product '', ISBN 1-932-59521-X

Europe

Contrary to popular belief, bathing and sanitation were not lost in Europe with the collapse of the Roman Empire. As a matter of fact, soapmaking first became an established trade during the so-called "Dark Ages." The Romans used scented oils (mostly from Egypt), among other alternatives. Also, contrary to myth, chamber pots were not emptied out the window and into streets in the European Middle Ages—this was instead a Roman practice. Bathing in fact did not fall out of fashion in Europe until shortly after the Renaissance, replaced by the heavy use of sweat-bathing and perfume, as it was thought in Europe that water could carry disease into the body through the skin. (Water, in fact, does carry disease, but more often if it is drunk than if one bathes in it; and water only carries disease if it is contaminated by pathogens.) Modern sanitation as we know it was not widely adopted until the 19th and 20th centuries. According to medieval historian Lynn Thorndike, people in Medieval Europe probably bathed more than Westerners did in the 19th century.http://www.godecookery.com/mtales/mtales08.htm

Grooming

The related term personal grooming/grooming means to enhance one's physical appearance or appeal for others, by removing obvious imperfections in one's appearance or improving one's hygiene.

Grooming in humans typically includes bathroom activities such as primping: washing and cleansing the hair, combing it to extract tangles and snarls, and styling. It can also include cosmetic care of the body, such as shaving and other forms of depilation.