The Mouthwash Debate

Most mouthwash users spit out the product, anyway. "I'm not concerned with the alcohol content unless you're gargling straight vodka," says Dr. Richard Price, the American Dental Association's consumer adviser. "I'm not worried about temporary dryness from alcohol mouthwash, if there is one."

Contrary to popular belief, the alcohol in mouthwash isn't killing germs. It's a carrier for essential oils (eucalyptol, menthol, methyl salicylate and thymol) that are the active ingredients in Listerine. "It's used to dissolve the flavor oils," says P&G's Doyle. "If the alcohol weren't there, it would separate just like salad oils. The flavor oils would float on top. Without the alcohol, Listerine would look like salad dressing." But the amount of alcohol in mouthwash is not enough to kill germs, he says. Listerine agrees that the alcohol in the product is not the active ingredient. "[The alcohol] dissolves the four essential oils [the active ingredients], so that they can make or effect their change on plaque," says Coelho.

The best way to get rid of bacteria: floss and brush teeth and clean the tongue twice a day. It's like showering to get rid of body odor, says the ADA's Price. "You're not really killing bacteria when you're taking a shower. You're physically removing them." After they bathe, people put on deodorant—just as they use mouthwash after they brush their teeth. "The mouthwash is not as important as physically removing the bacteria. You don't need a mouthwash," says Price.

"You need to do mechanical cleaning to make any inroads," says Peter Hurst, chief of dental surgery at Northwestern University's Feinberg School of Medicine. Sugarless gum and products like BreathStrips may help because they increase the flow of saliva. (The gums' odors can also "mask" bad breath, says Price. He notes, though, that artificial sweeteners can irritate the gastric tract and cause gas.) Dentists also recommend twice-a-year professional cleanings. And consider taking a self-assessment for periodontal disease at Perio.org.

A dry mouth leads to an "overgrowth of bacteria," says Dr. Susan Karabin, president of the American Academy of Periodontology. More than 200 medications can cause dry mouth, says the ADA's Price. Some asthma medications, Prozac-like antidepressants, antianxiety medications and diuretics can cause dry mouth and make people more prone to cavities and bad breath. "You don't have the saliva washing away the food," explains Karabin. "Saliva is our best natural defense against oral disease, other than a toothbrush, dental floss and diet," says Price. Breath is usually at its worst in the morning because the mouth (and saliva flow) "kind of goes to sleep" at night, says P&G's Doyle.

Several diseases and habits, such as eating a high-protein, low-carb diet, can worsen breath. Sinus problems and post-nasal drip can too. People with stomach acid coming up also notice a foul odor. "They'll report smelling or tasting their food after they've eaten it," says Dr. Udayan Shah, a pediatric otolaryngologist at the Nemours/Alfred I. duPont Hospital for Children in Wilmington, Del., an associate professor of pediatric otolaryngology at Jefferson Medical College in Philadelphia and a member of the American Academy of Otolaryngology's tonsil and adenoid subcommittee. Sometimes tonsils can harbor disease too, since food debris can build up there. In some people the resulting yellowish-white or greenish-yellow secretions are "the size of cottage cheese curds," says Shah. Some people may even need to get their tonsils removed for this reason. Gargling with water, water and baking soda or mouthwash can help.