In recent years, more people are worrying about halitosis (bad breath). Particularly, not a few young patients have symptoms known as psychosomatic halitosis (olfactory reference syndrome) in which halitosis causes introverted personality or always worries them regardless of the presence or absence of halitosis. Halitosis is said to be mostly caused by daily oral care such as tooth brushing. However, some are caused by periodontal disease or other diseases. In our clinic of Halitosis, we examine the presence or absence of halitosis by quantifying with a halitosis tester and provide an appropriate treatment after investigating the cause of halitosis below. We treat the symptoms considering the psychological care of patients.