Jerry was in fine form as he stood at center stage, his hand resting on the microphone stand, waiting for the laughter to subside. He had invited me to watch him perform stand-up at this West Los Angeles comedy club, and he didn’t disappoint. But his wife, Sandy, wasn’t laughing. She leaned across the small cabaret table we were sharing and said, 
“I need to talk to you about Jerry.” They had both been patients of mine for many years. Both were late middle-aged, and neither had ever had a serious medical problem. I looked at her quizzically and she said, “His breath.”

I leaned closer and asked, “What about his breath?”

“It’s different. Not bad, but it’s changed. Something’s not right.”

“How long?”

“Maybe three months.”

I asked if anyone else had mentioned anything, and she shook her head.

“How does he feel?”

“He says he feels fine. But something is wrong. I’m his wife and I can tell. Something has changed.”

I looked up at Jerry. He was pulling faces now, mimicking his elderly father as part of his routine. The audience was loving it.

“Have him come see me in the office,” I told Sandy.

“Honest to God, doc, I’m fine,” Jerry insisted a week later. “If you ask me, I think it’s my wife’s sniffer that needs a checkup.” Jerry did indeed look well, and when I put my face close to his and asked him to exhale through an open mouth, I could detect no unusual or unpleasant odor. Likewise, when I had him breathe out through his nose, nothing struck me as especially noxious.

He told me there had been no recent dental problems, sores in his mouth, or other symptoms. He didn’t wear dentures and hadn’t begun using any new medications or supplements. The examination of his nose, mouth, tongue, throat, and gums was unremarkable to my internist’s eye. I took one more sniff. Nothing. Frankly, I wasn’t sure that anything was wrong, but I told him to go see his dentist.

“I was just there three months ago,” he protested. “Everything was OK.”

I nodded and said, “See him again anyway.” Halitosis, defined as a foul or fetid odor carried on the breath, originates in the oral cavity or sinuses 80 to 90 percent of the time. The literature reports that it occurs in about 15 to 30 percent of the population. Since it is often difficult to notice one’s own odor, millions of people walk around with bad breath and don’t know it.

The malodor of halitosis usually results from the bacterial breakdown of amino acids in food debris, saliva, blood, and postnasal drip in the oral cavity. The residue of everything from caviar to cannoli provides the raw material for the volatile sulfur compounds primarily responsible for the offensive smell. Concentrations of the culpable microbes are particularly heavy in the spaces between the teeth and gums and on the back of the tongue.

The nasal passages and sinuses are the second-most common source of bad breath. Less common causes in the mouth are diseases such as gingivitis. Although an assortment of illnesses—such as advanced kidney disease and liver failure—can cause unpleasant odors on the breath, it is rare for any of them to produce halitosis without any other signs or symptoms.

Two weeks later I got a call from Sandy. “So, what did the dentist find in your husband’s mouth?” I asked.

“Nothing,” she told me. “The dentist didn’t even think his breath was bad. He just told him to floss regularly and gave him a toothbrush. But I know something’s wrong. Can’t you just give him some antibiotics?” She was obviously frustrated.

I told her I didn’t think that was a good idea. Although interdental and gingival sources of malodor may be transiently improved with antibiotics that suppress bacterial counts, in Jerry’s case I didn’t know what, if anything, I would be treating. “Let me see him in the office again,” I suggested.

The following afternoon both Jerry and Sandy sat in my exam room. When I asked him how he was feeling, Jerry said he was still doing just fine. “But my wife smells ghosts,” he quipped. He and I smiled and looked over at Sandy.

“I am not crazy,” she insisted.

“Of course not,” I said. I asked her if she had noticed changes in the odor of any other things that she smelled—foods, other people’s breath. She shook her head vigorously before I was even done asking the question. “No. It’s not me. I checked.” She went on to tell me that she’d had Jerry take an over-the-counter ulcer medication for a week in case a stomach problem was the cause, but it hadn’t made any difference.