Roughly 15 of every 1,000 people in the US have smell disorders

Anosmia is the total loss of the sense of smell

This type of loss—due to disease or trauma—has ripple effects, including an altered or limited sense of taste. This video details the anatomy and physiology of our sense of smell and taste and how these senses are interrelated.

Loss of sense of smell is a common symptom of COVID-19 infection

In 2020, researchers discovered why this occurs. The virus that causes this infection attacks the cells that support smell-detecting neurons. Once infection clears, the sense of smell typically returns, though the exact timeline for that differs by patient. (Some users may experience a paywall.)

1 in 15 adults over age 40 experience phantom odors

This phenomenon was measured in a 2018 study that examined the prevalence and risk factors for phantom odor perception. Older adults were less likely to experience these phantom odors as they age, just as their overall sense of smell declines. Women are more likely than men to perceive phantom odors.

Smell retraining can help people with anosmia learn to smell again

Olfactory training, which involves repeatedly smelling a selection of strong odors, teaches your brain to familiarize itself with experiencing smells over a lengthy period, typically multiple months. This can be useful for patients who lose their sense of smell for myriad reasons.

Hereditary hyperosmia is the official term for being a super-smeller

Some sniffers with this rare trait may be more sensitive to pleasant smells, while others may be more attuned to unpleasant scents. Some research suggests that certain genetic mutations are associated with a heightened sense of smell.

Humans may be able to distinguish more than one trillion scents

That's according to one estimate published in 2014. This figure far exceeds earlier estimates of a human smelling ceiling around 10,000 odors. The newer figure is derived from experiments in which volunteers agreed to sniff varying scents. Researchers mixed odor components and had volunteers sniff the brews to detect subtle scent differences. (Some users may experience a paywall.)

Smell is a robust memory cue for individuals with Alzheimer's disease

Odor is more effective than both visual and verbal cues for triggering autobiographical recall in Alzheimer's disease, according to 2021 research.

A super-sniffer smelled her husband's Parkinson's disease years ahead of symptoms

She discovered she could smell diseases, including Parkinson's, tuberculosis, Alzheimer's, cancer, and diabetes. Working with an analytic chemist, she's learned she can smell subtle changes in odor—ones that smell consistent across individuals with the same disorder—even before symptoms manifest.

Newborns have a strong sense of smell

Babies are drawn to their mother's smell—and the particular odor of their mother's breast milk—within days, even as their vision remains blurry for months after birth. In the womb, the olfactory center also forms in the early stages of development.

On average, people smell worse if they're sick

For a small 2014 research study, a panel was tasked with sniffing the smelly t-shirts of people who had been injected with a compound known to activate the immune system and those of controls without the shot. It found that those who were acting as if unwell (due to the injection) generally smelled worse. Subsequent work found that those who sniffed unpleasant odors had a mild immune response of their own—perhaps to protect them from disease. (Some users may experience a paywall.)

Roughly 1 in 125 people have autism spectrum disorder globally

The disorder has been increasingly diagnosed as its definition has grown broader and as clinicians have become more adept at identifying it—with some estimates suggesting the figures are much higher. These figures include people across the spectrum, some of whom live mostly independent lives, while others require life-long care and assistance.

Carboxylic acids are one reason teens are smelly

Scientists compared the smells of babies and teenagers and identified some of the compounds that make teens smelly. Carboxylic acids present in teens, they wrote, seemed to give off an "earthy, musty, or cheesy" scent. This 2024 research could help inform future odor-control products.

Americans only became intolerant of body odor in the last century

Daily bathing only became a societal norm in the last century. Today, Americans routinely bathe and buy more deodorant than any other country, spending roughly $6 billion annually on odor-reducing products. The rise of industrialized soaps, deodorants, and antiperspirants—and extensive marketing around them—stimulated this demand.

Typhoid smells like freshly baked brown bread

Certain ailments are associated with documented scents, including diabetes, Parkinson's disease, and typhoid. The skin of people with yellow fever, for example, can smell like a "butcher shop."

Examining self-diagnosed synesthesia

A growing number of people on social media claim to have a perceptual condition that lets them smell colors, see music, or taste sounds. But do they really?

Always forget a face? The science of face-blindness

Faces and names don't always go together in some people's minds. While everyone forgets other peoples's names occasion, people diagnosed with prosopagnosia can't recognize faces, much less names. Even friends can family members can appear to be strangers. This article covers the diagnosis and issues attendant to prosopagnosia and its sufferers.

More than 90% of American deaf children are born to hearing parents

The National Institute on Deafness and Other Communication Disorders have collated top statistics about hearing loss in the US including differences by age, racial groups, and other factors.

Roughly 1 in every 4,300 individuals in the US has mitochondrial disease

Roughly 1,000 to 4,000 kids are born with these conditions each year in the US though many of the diseases are fatal. Mitochondrial disorders often affect the organs that require the most energy, including the heart, brain, and muscles.

Most people breathe fungal spores daily without getting sick

Most people breathe in hundreds of Aspergillus fumigatus spores daily without getting sick—it’s a common microscopic fungus in our environment. But people who are severely ill, including those who have undergone an organ transplant, are at risk of developing infections from these spores.

A closer look at why people snore

Snoring is simply noise caused by improper airflow during sleep—and while it’s something that most people will do at some point in their lives, it can also be indicative of larger health problems. Generally speaking, snoring occurs when soft...

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens

This type of extreme reaction to harmless holes, dots, cracks, and seed collections can be debilitating for those who have it, but it is not an officially recognized disorder in the DSM-5.

Up to 225 cases of leprosy in the US are diagnosed each year

Most cases in the US are imported, meaning someone was infected in a country where it was more common. Since symptoms can sometimes take decades to appear, tracing the origin of the disease can be hard.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Alcohol use disorder is the most common addiction in the US

This comprehensive overview from the Addiction Center uses recent data from SAMHSA’s National Survey to examine the 10 most common substance dependencies in the United States. It ranks addictions from alcohol (affecting 28.3 million Americans) to barbiturates, while highlighting key trends, risks, and societal impacts.

SAD 101 from the folks at NIMH—where the condition was first identified

Norman Rosenthal led the team at the National Institute of Mental Health that first identified and described seasonal affective disorder in 1984. This 101 from NIMH explores the basics of the condition, from who develops it to how it is treated.

Roughly one in every 250 has never remembered a single dream

Most people dream for about two hours every night and recall about two dreams per week, and memory encoding is especially fragile upon waking. Alarms can knock dreams right out of one's head, and dream recall may be influenced by personality, interest, and socialization.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

11 people died from firework injuries in the US in 2024.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Despite being favored by 87% of Americans, Congress does not have term limits.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

The story of Dollree Mapp, whose legal challenge over her 1957 conviction for possessing "obscene material" led to a major strengthening of the Fourth Amendment

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

The United States has had a tumultuous relationship with Cuba since its 1959 revolution, highlighted by a nuclear crisis and a decades-long trade embargo.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Quincy Jones' 'Big Band Bossa Nova' helped introduce bossa nova—a jazz-influenced Brazilian genre—to the US

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born