94 Fun Facts About Hygiene

Hygieia, the Greek goddess of health, was usually called the daughter of which god of medicine?

Asclepius and Hygieia were worshipped in the same healing temples; her name shares a root with 'hygiene', and her sister Panacea's still means a cure-all.

The US CDC recommends scrubbing your hands with soap for at least how long?

20 seconds is about the time it takes to hum 'Happy Birthday' twice; the scrubbing is what counts, so the water can be warm or cold.

Who introduced chlorinated-lime hand disinfection in Vienna's First Obstetrical Clinic in 1847?

Ignaz Semmelweis saw childbed-fever deaths fall dramatically once doctors washed in chlorinated lime, yet the profession rejected his idea and he lost his post.

Evidence of soap-like materials being made dates back to around 2800 BC in which ancient civilisation?

Babylon: clay cylinders of about that date held a soap-like material and carried an inscription about boiling fats with ashes, which is still the basic recipe for soap.

The first bristle toothbrushes were made with bristles from which animal?

Hog bristles from cold northern regions were prized for their stiffness and set in bamboo or bone handles; Europeans later found them too harsh and switched to softer horsehair.

Which company introduced nylon toothbrush bristles, replacing animal hair, in 1938?

DuPont's nylon went on sale as toothbrush bristles in 1938, the new fibre's first commercial use; the stockings that made it famous only followed later.

What did dental floss inventor Levi Spear Parmly recommend running between teeth in 1819?

Waxed silk thread, Parmly wrote in 1819, would dislodge the matter that no brush can remove; even so, nobody sold floss commercially until 1882.

The first modern commercial deodorant, developed in Philadelphia in 1888, was sold under what name?

Mum was a zinc cream rubbed on with the fingertips; its makers say the name honours the inventor's nurse, though another account ties it to the phrase 'mum's the word'.

The first commercial antiperspirant, launched in 1903, was called what?

Everdry came first, but the aluminum chloride in early antiperspirants sat in acid that irritated the skin, until Jules Montenier's 1941 patent tamed it.

The English word 'shampoo', dating to 1762, comes from a Hindi word meaning what?

To press or knead is what the Hindi root means, and when 'shampoo' entered English in the 1760s it meant to massage someone, not to wash their hair.

The earliest recorded use of paper for toilet hygiene, in the 6th century AD, comes from which country?

China: around 589 the scholar Yan Zhitui wrote that he dared not use paper bearing the names of sages for toilet purposes, so plain paper was clearly already in use.

Joseph Gayetty's Medicated Paper of 1857, an early commercial toilet paper, was treated with which plant extract?

Aloe was worked into each flat sheet as a lubricant, and Gayetty, who had his name watermarked on the paper, sold it as a medical aid for haemorrhoids.

Which company popularised toilet paper on rolls when it began marketing them in 1890?

Scott at first kept its own name off the rolls because of the nature of the product, leaving dealers to sell them under brand names of their own.

Which pioneer of antiseptic surgery gave his name to a mouthwash developed in 1879?

Joseph Lister, the antiseptic-surgery pioneer, inspired the name of Joseph Lawrence's Listerine of 1879, first sold as a surgical antiseptic and floor cleaner before becoming an over-the-counter mouthwash in 1914.

Listerine sales exploded in the 1920s when it was sold as the cure for which then-obscure term?

Halitosis was a real but obscure medical word, from the Latin for breath, when Listerine's ads made it a household fear; the product had earlier been sold as a floor cleaner.

Which hygiene habit has had its own global day every 15 October since 2008?

Washing your hands with soap is the message of Global Handwashing Day; at the first one, more than 120 million children in over 70 countries took part.

The CDC recommends alcohol-based hand sanitizer containing at least what percentage of alcohol?

60% is the minimum the CDC accepts, and even then the gel is only a fallback: the advice is to use it when soap and water are not available.

Which chemical did Joseph Lister introduce at the Glasgow Royal Infirmary in 1865 to sterilise wounds and tools?

Carbolic acid caught his eye because it was being used to treat sewage; in August 1865 he dressed a boy's badly broken leg with it and the wound healed without infection.

In 1854 John Snow traced a London cholera outbreak to a public water pump on which Soho thoroughfare?

Broad Street, now Broadwick Street: Snow mapped the deaths, found them clustered round its pump and got the parish to take the handle off; the well turned out to sit beside a leaking cesspit.

Joseph Bazalgette built London's main sewer system in response to which event of 1858?

The Great Stink of summer 1858, when the sewage-filled Thames reeked so badly that Parliament's curtains were soaked in chloride of lime, pushed MPs to fund Bazalgette's sewers, which helped end London's cholera epidemics.

The US Army issued King Camp Gillette's safety razors to its soldiers during which war?

World War I put a government-paid Gillette kit in every American serviceman's pack, and millions of men came home in the habit of shaving themselves every day.

What does the Q stand for in Q-tips, the cotton swabs Leo Gerstenzang first sold as Baby Gays?

Quality: Gerstenzang got the idea in 1923 from watching his wife stick wads of cotton on toothpicks, and the swabs were Baby Gays before the Q-tips name took over.

The word 'bidet' is French for what?

Bidet means 'pony' in French, because the user straddles the fixture as a rider sits a small horse; the word probably comes from an Old French verb meaning to trot.

Sir John Harington, who described a forerunner of the flush toilet in 1596, was the godson of which monarch?

Elizabeth I's 'saucy godson' built his water closet at his own house at Kelston and named it Ajax, a pun on 'a jakes', the slang of the day for a privy.

Alexander Cumming's 1775 patent for what device laid the foundation of the modern flush toilet?

Cumming's 1775 patent covered the S-trap, a bend that keeps standing water in the pipe to seal out sewer gases, together with a sliding valve beneath the bowl.

Which slogan did Ivory soap introduce in 1891?

'It Floats!' became Ivory's slogan in 1891, trading on the air whipped into the soap mixture that let the bar bob to the surface of the bath.

In 1945, Grand Rapids, Michigan, became the first city to add what to its water?

Fluoride was tried after dentists traced Colorado's stained but decay-resistant teeth to the local water; in the years that followed, tooth decay among the city's schoolchildren fell sharply.

The Broxodent, the electric toothbrush Dr. Philippe-Guy Woog designed in 1954, came from which country?

Switzerland: Woog built the Broxodent there for patients with limited motor skills and people wearing braces; an American electric brush, the Motodent, had a patent filed back in 1937.

Which emperor gave his name to the enormous Roman baths, complete with libraries, finished around 216 AD?

Caracalla's baths could hold some 1,600 bathers at once and had separate Greek and Latin libraries; centuries later their halls helped inspire New York's original Penn Station.

Which 1990 self-help book by sleep researcher Peter Hauri laid out sleep-hygiene rules?

No More Sleepless Nights (1990), by Peter Hauri and Shirley Linde, brought sleep-hygiene rules to a popular audience; Hauri had first set them out for clinicians in 1977.

Florence Nightingale's famous 'rose' diagrams showed that most British soldiers in the Crimean War were dying of what?

Preventable disease: illnesses such as typhus, cholera and dysentery killed far more men than wounds did, and her polar area diagrams drove the point home to the government.

Which French and German pair are most associated with proving the germ theory of disease?

Louis Pasteur and Robert Koch: Pasteur's swan-neck flasks disproved spontaneous generation in the 1860s, and Koch's postulates and his 1882 identification of the tuberculosis bacillus tied specific germs to specific diseases.

Which Greek physician recommended a mouth rinse of salt, alum and vinegar around 400 BC?

Hippocrates trusted the rinse, but two thousand years later Leeuwenhoek put vinegar mouthwash to the test under his microscope and found the organisms in dental plaque still alive.

Ban Roll-On, launched in 1952, borrowed its applicator from which newly popular invention?

Ballpoint pen: in the late 1940s Helen Barnett Diserens, working for the maker Bristol-Myers, copied its rolling ball so that liquid deodorant could be rolled onto the skin.

In 1873, which company began mass-producing aromatic toothpaste sold in jars?

Colgate had spent its first 67 years making soap, starch and candles before it put an aromatic toothpaste in jars in 1873; its first tube followed in 1896.

Nicolas Leblanc's 1791 process made soap far cheaper by turning which everyday substance into soda ash?

Common salt replaced the plant ashes that soap makers had imported for their alkali; Leblanc gained little, since the Revolution seized his factory and never paid his prize.

What are ancient Romans traditionally thought to have shared in public latrines in place of toilet paper?

A sponge on a stick, kept in vinegar or salt water between users, is the traditional answer, though some researchers now argue it was really the latrine's toilet brush.

How often should a healthy adult replace their toothbrush, according to standard advice?

About every 3 months: the American Dental Association says three to four, or sooner if the bristles look frayed, because a worn brush cleans less well.

England's NHS advises against doing what immediately after brushing your teeth?

Rinsing with water washes away what the toothpaste leaves behind to protect the teeth, so the NHS says to spit out the excess and stop there.

Alcohol-based hand sanitizers may not work well in which situation?

On visibly soiled hands, or greasy ones, the gel may not do its job, so the advice is to wash with soap and water instead and save sanitizer for hands that look clean.

Sleep hygiene recommendations were first developed in the late 1970s to help people with what?

Mild to moderate insomnia was the target when the advice was drawn up in the late 1970s, yet later reviews found the evidence that sleep hygiene treats it limited and inconclusive.

What broad term covers antiseptics, disinfectants and pesticides alike?

Biocide is broad enough that one EU regulation covers hand disinfectants, rat poison and the antifouling paint on a ship's hull as product types of the same thing.

Which label means a disinfectant kills the dormant, highly resistant form of bacteria?

Sporicidal products kill bacterial spores, the toughest target of all; ordinary alcohol hand gel, for one, works against most microbes but not against spores.

Which Roman emperor defended his tax on public urinals with the remark that money does not stink?

Vespasian taxed the urine that launderers and tanners bought from public urinals; Suetonius says that when his son Titus objected, he held a coin under his nose and asked if it smelled.

Which billionaire drank water made from human sewage to promote his foundation's work on sanitation?

Bill Gates sipped water from the Omni Processor, a plant that turns sewage sludge into drinking water and electricity. His foundation also set engineers the Reinvent the Toilet Challenge.

Which disposable tissue brand was first sold as a cold-cream remover rather than for blowing noses?

Kleenex was pitched for wiping off make-up until the 1930s, when adverts recast the sheets as disposable handkerchiefs and that use took over.

Mary Mallon, a New York cook with no symptoms herself, infected the families she worked for with which disease?

Typhoid fever followed Mary Mallon from kitchen to kitchen, earning her the nickname Typhoid Mary. Officials confined her on North Brother Island in New York's East River.

Why do food-safety agencies tell cooks never to wash raw chicken before cooking it?

It splashes germs around the kitchen onto clean surfaces, and Britain's food-safety agency ran a whole campaign against the habit. Campylobacter, the main culprit, can be very numerous on raw poultry.

Lice that live in children's hair cannot jump or fly, so which route accounts for most of their spread?

Head-to-head contact is by far the commonest route, since the insects can only crawl from one hair to the next. Cats and dogs play no part, and neither does dirty hair.

Which Nordic country, home to at least two million saunas, gave English the word 'sauna' itself?

Finland has about 5.5 million people, so that is roughly one sauna for every two or three residents. The Finnish Sauna Society puts the true figure as high as 3.2 million.

Which outer layer of a tooth, the hardest substance in the human body, is slowly dissolved by acids from plaque?

Enamel is 96% mineral and has no way to regenerate itself, so the body cannot replace whatever acid wears away.

Health agencies advise coughing or sneezing into which body part when no tissue is available?

Elbow or upper-sleeve sneezing keeps droplets off the hands, which go on to touch door handles, phones and other people. Looking down as you sneeze helps too.

Bacteria in dental plaque feed on which food ingredient, producing the acid behind tooth cavities?

Sugar feeds decay bacteria, which turn it into lactic acid. After each sugary snack, minerals at the tooth surface can stay dissolved for two hours.

The American Dental Association recommends brushing teeth twice a day for how long each time?

2 minutes is the mark at which many electric toothbrushes buzz or briefly cut out, a built-in timer for the standard advice.

What do dentists call dental plaque that has hardened into a deposit only professional cleaning can remove?

Tartar, or dental calculus, forms when minerals from saliva settle in plaque. Its rough surface then gives fresh plaque an ideal place to cling.

Which early gum disease, reversible with good brushing, makes gums red, swollen and quick to bleed?

Gingivitis clears up once plaque is kept off the gumline. Left alone it can progress to periodontitis, which destroys the bone that holds teeth in place.

Which part of the mouth, when coated with bacteria towards the back, is the commonest source of bad breath?

Tongue coating is the usual culprit, which is why cleaning it is among the first remedies suggested, alongside mouthwash and flossing.

Body odour usually first appears at which stage of life, when rising hormones change the make-up of sweat?

Puberty brings a surge of androgens, hormones that also make the skin oilier and start underarm hair growing.

Which skin condition, affecting most teenagers, starts when oil and dead skin cells clog hair follicles?

Acne has nothing to do with being dirty: cleanliness is not linked to it, and susceptibility is mainly inherited.

Which itchy, peeling condition between the toes is often picked up barefoot in public showers and locker rooms?

Athlete's foot affects about 15% of people worldwide, sporty or not. Tight shoes and socks worn for more than a day both raise the risk.

Ringworm, the itchy ring-shaped skin rash common in children, is caused by which kind of organism?

Fungus, not a worm: about 40 types can cause ringworm, which spreads through shared showers, contact sports and contact with animals.

Antiperspirants block sweat ducts with gel plugs formed by compounds of which metal?

Aluminium salts react with sweat to form temporary gel plugs in the ducts, which wear away as the skin sheds. A plain deodorant only tackles the smell.

Which glands, found mainly in the armpits and groin, make the oily secretion that bacteria turn into body odour?

Apocrine glands release a cloudy, oily fluid that has no smell at all until microbes on the skin break it down.

Which oily substance, made by glands that open into hair follicles, lubricates the skin and hair?

Sebum is made most heavily on the face and scalp, which is why those turn greasy first. The palms and soles have no such glands at all.

Which intensely itchy skin infestation is caused by a tiny mite that burrows into the skin to lay eggs?

Scabies, sometimes called the seven-year itch, is contagious and usually passes on through prolonged skin-to-skin contact with someone who has it.

What name is given to the eggs of head lice, found attached to hair shafts close to the scalp?

Nits gave English the word 'nitpicking', from the slow job of removing each one from another person's hair by hand.

Which flaky scalp condition affects about half of all adults, more often men than women?

Dandruff is thought to arise when scalp skin cells mature and shed in two to seven days rather than the usual month or so.

Which contagious skin infection of young children forms honey-coloured scabs around the nose and mouth?

Impetigo is caused by bacteria, usually staph or strep, getting into the top layer of skin, and it is most common between the ages of two and five.

Which common nervous habit is known to doctors as onychophagia?

Nail biting can damage the fingers and cuticles and turn the hands into a route for infection.

What is the medical name for earwax, the secretion that traps dust before it can reach the eardrum?

Cerumen comes in two inherited types, wet and dry, and a single DNA letter change in one gene decides which a person makes.

Which contagious eye infection, known as pink eye, often spreads when children rub their eyes with unwashed hands?

Conjunctivitis inflames the thin, clear layer that covers the white of the eye and lines the eyelid. Good hygiene is the most effective way to prevent it.

Contact lenses should never be washed in which liquid, home to the sight-threatening microbe Acanthamoeba?

Tap water can carry Acanthamoeba, which survives in the gap between lens and eye. Bathing or swimming in lenses carries the same risk.

Which antibiotic-resistant 'superbug' spreads in gyms and locker rooms through skin contact and shared towels?

MRSA is a group of staph strains that shrug off a whole family of antibiotics. Sports teams are a high-risk group, so showering after exercise and not sharing razors are advised.

The 'hygiene hypothesis' suggests that very clean, infection-free childhoods raise the risk of which conditions?

Allergies such as hay fever and asthma rose through the 20th century, and David Strachan proposed in 1989 that fewer early infections might explain why.

Which highly contagious stomach bug, nicknamed the winter vomiting bug, often sweeps through cruise ships?

Norovirus lacks the fatty outer envelope that alcohol attacks, so hand gels tend to fail against it and soap and water work better.

Which intestinal parasite, once widespread in the southern United States, gets in through the skin of bare feet?

Hookworm larvae hatch in soil fouled by human waste, and heavy infections can cause anaemia. John D. Rockefeller gave $1 million in 1909 to fight it.

Which disease, spread by body lice in crowded and filthy conditions, was once known as jail fever?

Typhus tends to follow wars and disasters, when crowding lets lice thrive. In old English jails it reportedly killed more inmates than the public executioners did.

Which Dutch microscope maker first described bacteria after examining plaque scraped from his own teeth?

Leeuwenhoek told the Royal Society in 1683 about the tiny 'animalcules' he saw, and found far more in two old men who had never cleaned their teeth.

Before germ theory took over, doctors blamed cholera and plague on which noxious 'bad air' from rotting matter?

Miasma thinking gave malaria its name, from the medieval Italian for 'bad air', and held on until germ theory displaced it after 1880.

Which chemical reaction between fats and a strong alkali such as lye is used to make soap?

Saponification takes its name from 'sapo', the Latin for soap, and the reaction releases glycerol alongside the soap itself.

Which birch-derived sweetener, common in chewing gum, is thought to curb the mouth bacteria behind cavities?

Xylitol occurs naturally in plums, strawberries and cauliflower, yet it is poisonous to dogs, so gum containing it should be kept well away from pets.

Which teeth-cleaning twig, cut from the Salvadora persica tree, is recommended in Islamic tradition?

Miswak use is frequently advocated in the hadith, the traditions about the life of the Prophet Muhammad, who is said to have used one regularly.

Which steam bathhouse of the Islamic world, modelled on Roman baths, do Westerners often call a Turkish bath?

Hammam layouts kept the Roman sequence of undressing room, cold room, warm room and hot room, with furnaces sending hot air under the floor.

Which Islamic ritual washing of the hands, mouth, face, arms and feet is performed before prayer?

Wudu follows a set order that ends with the feet, and where no water can be found the Quran allows clean earth to be used instead.

Which Japanese word names hot-spring baths where guests must wash thoroughly before stepping into the water?

Onsen water comes from geothermally heated springs, of which Japan has about 25,000. The same wash-first rule applies at a sento, the neighbourhood public bathhouse.

Which antibacterial ingredient, once found in most liquid soaps, did the US FDA rule out of consumer washes?

Triclosan was among 19 ingredients the FDA struck out in 2016, having seen no evidence that such washes beat plain soap and water.

Which eye infection, spread by flies and personal contact, is the world's leading infectious cause of blindness?

Trachoma is caused by the bacterium Chlamydia trachomatis. Repeated infections scar the eyelid until it turns inward and the lashes scratch the eye.

Which parasitic disease, nearly eradicated by a Carter Center campaign, is prevented by filtering drinking water?

Guinea worm struck an estimated 3.5 million people a year in 1986. Cloth and pipe filters strain out the tiny water fleas that carry its larvae.

Which curved metal tool did ancient Greek and Roman bathers use to scrape oil, sweat and dirt from the skin?

Strigil scraping followed a rub-down with oil, and the tools were used mainly by men who trained and competed in sport. Many have been found in tombs beside a bottle of oil.

Which Indus Valley city in Pakistan holds the Great Bath, called the earliest public water tank of the ancient world?

Mohenjo-daro's builders sealed the tank with finely fitted bricks, gypsum plaster and a thick layer of bitumen to keep it watertight.

Which English reformer's best-selling report on working-class squalor led to a landmark Public Health Act?

Edwin Chadwick researched and published the 1842 report at his own expense, and it became the Stationery Office's best-selling publication to date.

Which Indian-born entrepreneur opened 'shampooing' vapour baths in Brighton and became shampooing surgeon to George IV?

Sake Dean Mahomed had already opened the Hindoostane Coffee House in London in 1810, the first Indian restaurant in England.

Which painful condition crippled First World War soldiers whose boots stayed cold and wet for days?

Trench foot was first described during Napoleon's retreat from Russia in 1812. Changing into dry socks two or three times a day helps to treat it.

Which bacterium, a well-known cause of food poisoning, is the classic hazard of raw or undercooked eggs?

Salmonella is named after the American veterinary surgeon Daniel Elmer Salmon, and it spreads through contaminated meat, eggs, water or milk.