The intensity of the odor is variable, but researchers usually record the aroma as mild, moderate, pungent, objectionable and very objectionable. I leave it to your imagination to select appropriate examples of this classification. Medical risks for bad breath include bronchial and lung infections, chronic sinusitis, post-nasal drip, tonsillitis. The mucous discharge which comes during cold or flu can create bad breath. Also implicated are untreated nasal polyps, diabetes, syphilis, diseases of the stomach and lungs, liver, kidneys, and there is a type of halitosis which is caused by a gallbladder dysfunction.
Some medications can cause or exacerbate bad breath.
Various cancers can cause malodor. You should consult your physician if bad breath becomes chronic and the simple treatments detailed in this report don't work. However, these problems taken altogether affect a very small percentage of people. Stress or nervous tension is a major enhancer of bad breath. In fact, there seems to be a stress component to most bad breath.