Woman in Her 30s Faces Health Scare While Brushing Teeth in the Shower... Expert Issues Strong Warning: 'Stop Immediately' [Health Talk]

[The Financial News] Experts have warned that brushing your teeth while showering may increase the risk of bacterial infection. In particular, those with chronic lung diseases or weakened immune systems are advised to reassess their daily hygiene routines.
On the 21st, Seoul National University Hospital shared a video on its YouTube channel titled, 'Stop Immediately: Rinsing Your Mouth with the Shower Head,' delivering this message.
According to the video, rinsing your mouth directly with a shower head can raise the risk of infection by nontuberculous mycobacteria (NTM). NTM are a type of mycobacteria similar to those causing tuberculosis, but they are mainly contracted through environmental exposure rather than person-to-person transmission. These bacteria have been detected not only in natural environments like lakes, rivers, and soil, but also in household and medical water sources such as shower heads, water pipes, and humidifiers.
These bacteria are relatively resistant to chlorine disinfection and tend to survive by adhering to surfaces, making it easy for them to form biofilms inside shower heads or hoses. The structure of hoses, where water can easily stagnate, is particularly conducive to bacterial growth. When rinsing the mouth with water from the shower head, the oral cavity and upper respiratory tract are directly exposed to droplets, increasing the likelihood of inhaling bacteria.
Jaejun Lim, a professor of pulmonology at Seoul National University Hospital, emphasized, "If a shower head is old, bacteria can adhere inside and spread during use. The habit of rinsing your mouth with water from the shower head is something that should be stopped immediately."
He further advised, "Replace the shower head at least every six months, and pay special attention to hygiene if using an older product."

There have been international cases where this everyday habit was identified as the cause of infection. In November last year, a 39-year-old woman in China suffered from chronic coughing and was diagnosed with nontuberculous mycobacterial lung disease. Investigations revealed that she had not replaced her shower head for over 10 years. Medical staff suggested that her old shower head and the habit of rinsing her mouth with it were likely sources of infection.
However, medical professionals explain that simply showering or using tap water does not usually cause NTM disease. In most cases, healthy individuals are able to eliminate the bacteria through their immune systems without developing symptoms.
On the other hand, people with Chronic Obstructive Pulmonary Disease (COPD), Bronchiectasis, lung damage from previous Tuberculosis (TB), or those undergoing immunosuppressive therapy are at relatively higher risk of developing lung disease.
Experts recommend reducing infection risk by regularly detaching and cleaning shower heads and hoses, and ensuring water does not remain stagnant inside. For brushing teeth, it is safer to use tap water from the sink and avoid rinsing the mouth directly while showering.

The shower head can serve as a habitat for nontuberculous mycobacteria. While these bacteria do not spread from person to person, they can enter the respiratory tract through the air and cause lung disease.
Sources of infection include not only natural environments such as lakes, rivers, and soil, but also shower heads, humidifiers, and contaminated medical devices. Bacteria can also multiply in water left inside the shower head.
Simply showering or using tap water does not cause NTM disease. Healthy individuals do not need to worry.
However, people with COPD, Bronchiectasis, TB, or weakened immune systems should be cautious.
To prevent NTM infection from shower heads, it is important to maintain strict hygiene. Replace the shower head every six months and clean the inside frequently. Disassembled shower head parts should be soaked in diluted bleach and scrubbed thoroughly with a small brush.
moon@fnnews.com Moon Young-jin Reporter