Why don't people tell each other they have bad breath?

It's been a problem for as long as bad breath has, and today it's likely no better than it was thousands of years ago. Most people have terrible difficulty telling a friend, a co-worker or even a loved one that they have halitosis. Why is this so? There are any number of reasons, but what most of them have in common is the sometimes misguided need to spare another's feelings.

This need to avoid offending others who have oral odor may be a sort of philosophical cousin of the Hippocratic oath. The ancient Greek physician Hippocrates, who is commonly known as the father of Western medicine, had his own ideas about bad breath. He believed that a mixture of myrrh, white wine and aniseed oil could reduce the smell of halitosis. However, he also believed in the principle of primum non nocere - "first, do no harm."

While scholars have revealed that Hippocrates never said those three words himself - they're Latin after all, and he was Greek - their spirit pervades the Hippocratic oath, an ethical promise sworn by almost all modern physicians.

The problem is simple. Is it doing no harm to tell someone their breath smells, even if the person becomes enraged? Or is it doing no harm not to tell them, although their oral odor may couse problems for them later on down the line?

Many dental experts have weighed in over the years. An 1851 entry in the Water-Cure Journal, a long-defunct homeopathic periodical, certainly makes oral odor sound unappealing.

"What can be more disgusting to contemplate than...accumulated tartar on the teeth," the journal asks, "until the gums become a mass of putrid, ulcerated sores - evolving at every breath a stench unendurable. Horrible! Awful!"

If it can be so repulsive, should a person with bad breath be told? In a speech delivered in Washington, DC, in 1896, dentist H. Jerome Allen said yes, they should.

"Such is the universal false kindness of their friends and relatives," he said, "that, with the best intentions in the world, they would rarely whisper to them a word of their disorder or suggest a source of relief."

Today, these sources can include specialty breath freshening rinses, tongue scrapers, oral care probiotic products and foaming toothpastes, something to which people in previous centuries had little or no access.

Now, if only the Hippocratic halitosis paradox can be resolved, individuals with oral odor may find themselves aware of their predicament and armed to treat it.