Chronic bad breath may be caused by Helicobacter pylori infection, but this is not always the case. Other causes of bad breath include dental issues, such as cavities and tooth decay. Additionally, stomach diseases can also cause bad breath, many of which are associated with Helicobacter pylori infection. After ruling out dental diseases, it is recommended to undergo a Carbon-14 breath test to determine if there is an infection of Helicobacter pylori. If the test for Helicobacter pylori infection is positive and accompanied by some stomach symptoms, such as upper abdominal bloating, burping, acid reflux, nausea, and vomiting, it is advisable to undergo a 14-day treatment for Helicobacter pylori. Generally, after treatment, the Helicobacter pylori can change from positive to negative.