Bad breath, medically called halitosis, is an unpleasant odor of the breath, so it can have a significant impact on a person’s social and professional life. The most effective treatment is to treat the cause. Usually it can result from poor hygiene, when dentures are not properly cleaned, but it can be a sign of different health problems such as sores in the mouth, infected tonsils, indigestion, lung infection, kidney failure, tuberculosis, syphilis, liver disease, stomach and intestinal problems, stress, dehydration, zinc deficiency, and cancer. In addition, many other diseases and illnesses may cause bad breath. For example, persistent bad breath or a bad taste in your mouth may be also warning signs of gum periodontal disease.