In a newly published study, people who gargled every day with water had fewer colds than those who didn't gargle or those who gargled with an antiseptic mouth rinse containing iodine.
Iodine mouthwashes are popular in Japan due to the common belief that they protect against colds and flu.
The iodine rinse was not found to be protective in the new study. But gargling with water was.
The researchers found that people who gargled with water several times a day were more than one-third less likely to catch a cold.
"This study suggests that simple water gargling is effective to prevent upper respiratory tract infections among healthy people," Kyoto University public health researcher Kazunari Satomura, MD, and colleagues wrote.
But infectious disease specialist Aaron Glatt, MD, says the study falls far short of convincing him that gargling with water is an effective weapon against the spread of the common cold.
Glatt is a spokesman for the Infectious Diseases Society of America and is chief of infectious diseases at New York Medical College's Our Lady of Mercy Medical Center.
The study's researchers speculated that gargling with water might wash germs from the throat or mouth before they have time to spread. But Glatt says this idea doesn't hold water.
"It just doesn't make any sense," he tells WebMD. "If gargling with water protects against colds then why wouldn't you do the same thing every time you drink water or anything else."
Glatt says there were significant problems with the study, including the fact that all of the people enrolled knew which treatment they were getting.
"I can't believe (gargling with water) would have any benefit," he says. "I certainly wouldn't recommend it based on this study."
'Price Is Right'
Vanderbilt University professor of preventive medicine William Schaffner, MD, was also skeptical, but less critical of the study.
"My interest is certainly piqued, but these findings certainly need to be replicated," he tells WebMD. "But it would be wonderful if this easy, natural intervention really does reduce the risk of infection. And the price is certainly right."
A total of 387 healthy volunteers were followed for two months during cold and flu season.
One third of the participants were told to gargle with water at least three times a day, another third were told to gargle three times daily with a mouth rinse containing iodine, and the rest did not gargle at all.
During the study, 130 people caught colds or other upper respiratory infections.
There was no major difference in the rate of colds between the group that did not gargle and the group that gargled with the iodine solution. But there was a 36 percent decrease in infections in the group that gargled with water.
The study was published in the November issue of the American Journal of Preventive Medicine.
Sources: Satomura, K., MD, American Journal of Preventive Medicine, November 2005; online edition. William Schaffner, MD, professor of preventive medicine, chief of preventive diseases, Vanderbilt University Medical Center. Aaron Glatt, MD, assistant dean and professor of medicine, New York Medical College; chief, infectious diseases, Our Lady of Mercy Medical Center, New York; spokesman, Infectious Diseases Society of America.
By Salynn Boyles
Reviewed by Michael W. Smith, MD
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