Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Font Size

Your Sense of Smell May Be Keener Than Thought

Study suggests people can detect more than a trillion distinct odors

WebMD News from HealthDay

By Alan Mozes

HealthDay Reporter

THURSDAY, March 20, 2014 (HealthDay News) -- The human nose may be far more discerning than thought, with new research suggesting it can sniff out more than 1 trillion separate scents.

"It has often been said that humans can distinguish [only] 10,000 different smells," said study co-author Andreas Keller, a research associate with the laboratory of neurogenetics and behavior at Rockefeller University in New York City.

But this latest finding suggests that humans can sort through more than 1 trillion smells, which is far more than the number of colors and tones that human eyes and ears can pick out, he said.

What accounts for smell's lesser reputation?

"We tend to distrust our sense of smell because we are bad at identifying and naming smells," Keller said. "But naming and identifying smells is not what our olfactory system evolved to do. Instead, it evolved to allow us to discriminate very similar smells, like the smell of food and the same food with the slightest hint of being spoiled. Our study shows that we are very good at this type of task."

Keller and his colleagues discuss their findings in this week's online issue of the journal Science.

The current investigation was predicated on the notion that odors are actually the end product of a complex mixture of molecular compounds. The scent of a rose, for example, is actually comprised of 275 different components, the study authors said.

That said, the researchers set out to assess nasal sensitivity by collecting relatively simple odor compounds, each containing just 10 to 30 different building blocks, drawn from a limited pool of 128 odor molecules.

Odor cocktails were then unveiled in 260 different groups of three, before 26 adults -- 17 women and nine men, all aged 20 to 48. Two odor vials contained the same concoction, while the third vial was different, and participants were asked to sniff out the so-called "odd" odor.

After discounting for the possibility of simply guessing the right answer, the authors found that smell-testers were able to accurately discriminate odd odors 54 percent of the time.

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing