If bad breath occurs during the menstrual period, the best thing to do is to brush your teeth carefully, rinse your mouth with mouthwash, and consider going to the hospital for dental cleaning treatment as soon as possible after the menstrual period. During the menstrual period, the gum tissue inside the mouth is particularly susceptible to inflammatory reactions due to changes in the body’s hormone levels, and this is when bad breath can be noticeable. Some traditional beliefs say that you should not brush your teeth during the menstrual period because doing so will aggravate bad breath. It is scientifically believed that normal brushing and rinsing with warm water can also be applied during the menstrual period, and that the gum tissue can only be healthy if the bacterial infectious material around the teeth is cleaned out. Going to the hospital for scaling after the menstrual period can also clean out the calculus around the teeth and the gum tissue will slowly return to health.