The origin of halitosis is in the millions of bacteria.

90 per cent of the causes of bad breath originate in the mouth. Usually, the origin of halitosis is in the millions of bacteria that live in the oral cavity and are able to produce volatile compounds sulfated very bad smell. Moreover, this problem can be strengthened with dentures or if they suffer from mouth sores, tooth decay, sinusitis, infections in the gums or dry mouth. In some cases, halitosis can occur as a result of any illness as a poorly controlled diabetes (sweet-smelling breath) or chronic renal failure (breath smelling like ammonia), although the existence of these diseases does not necessarily mean the emergence of halitosis. Another reason that can cause bad breath are the poor diets in carbohydrates, nutrients present in foods like pasta, potatoes, bread, rice, cereals and legumes. Over time, the lack of carbohydrates causes the body to start using fat for energy. This produces ketosis, which is an increase in blood and urine levels of ketene bodies. Ketene bodies are some compounds that appear as a result of the metabolism or use of these fats for energy. One of the characteristics of ketosis is the emergence of a sharp breath odor due to the elimination of small amounts of acetone. Among the children is very common this problem, which in many cases is due to the introduction of foreign bodies in the nasal passages, to food allergies, tonsillitis or to any of the conditions mentioned above. Anyway, it is always advisable to go to the doctor to perform a proper diagnosis and discover the cause that triggered the foul odor.