Seattle Dentists Test Cure for Bad Breath: Gargle Your Spouse's Mouth Bacteria, Which Most Marriages Have Been Doing for Free

Science has finally answered the question nobody at the dinner party was brave enough to ask. The cure for your breath may be somebody else's mouth.

Researchers at the University of Washington School of Dentistry are testing oral bacteria transplants for chronic halitosis, a first-of-its-kind trial in which bacteria are collected from a healthy donor, suspended in saline and given to a patient as a mouth rinse. It is the probiotic aisle, but with a face. Donors should ideally be "an intimate partner, family member or trusted friend," making this the first medical form in history that doubles as a loyalty test.

The procedure is elegant the way a hostage exchange is elegant. The donor gets a full periodontal exam, because even spit now needs references. The recipient gets a deep cleaning to disrupt the biofilm, the thin, sticky layer of microorganisms that has been living in their gums rent-free for years. Then the patient rinses with the donor solution, and researchers inject a concentrated version into the gumline. Nobody says "cheers." Everybody thinks it.

"What we're trying to do is severely disrupt the original bacteria, and then we bring in the new guys to take hold and establish a new biofilm," said co-lead Alex Pozhitkov. "It's a numbers game." That is also how every war, every startup and every church potluck has been described. Your mouth is now a hostile takeover, and the board has already voted.

Co-lead Alvin Wee, a professor of restorative dentistry, put it plainly: "We know the oral microbiome can get out of whack. The question is, can you rebalance it?" Philosophers have asked that about the human soul for three thousand years. Dentists skipped the philosophy and went straight to the saline.

The stakes are not small. OPB, reporting on the trial today, noted that up to half of adults suffer from chronic bad breath, although estimates vary. Estimates vary because nobody wants to be the one holding the clipboard. OPB even offered a home test: "Breathe into your hand and give that air a sniff." Millions of commuters have now done it and are pretending to adjust their scarves.

The idea builds on fecal microbiota transplants, which means the mouth is, medically speaking, the sequel. Like most sequels, it is smaller, weirder and nobody asked for it, but everyone agrees it beats the original.

So far the team has completed four transplants. Ninety days later, participants self-report whether their breath has improved. Self-reporting is the weakest link in this science, because no human being has ever smelled their own breath and told the truth. The researchers are seeking federal approval for a larger cohort, with testing expected to run up to two years. The funding comes from the Dean and Margaret Spencer Clinical Research Fund, two names now permanently attached to the phrase "your husband's mouth germs."

The social consequences will be enormous. Wedding vows will need a new clause. Group chats will need a secret ballot. Somewhere, a man will ask his brother for a kidney, be told no, and then ask for something far more intimate.

The researchers hope the healthy bacteria will crowd out the bad. It is the oldest advice in the world: choose your friends carefully. Now, apparently, you also gargle them.