At night our mouth becomes dry leading to accumulation of bacteria causing bad breath in the morning. Those who breathe through their mouth at night experience more bad breath.

Chronic bad breath may also be due to any hidden medical disease. A bad breath having fishy smell might indicate chronic kidney failure. Diabetic people having lack of glucose in blood to process energy experience a fruity odor in breath. Sinusitis, lung infections may also give bad breath. In sinus infections nasal discharge that drips from the sinuses to the back of your throat can cause malodor. The respiratory infections containing ulcers, malformed basal cavity or even tonsils provide a very favorable environment for the odor-causing bacteria to multiply.

Cigarettes contain 4000 chemicals out of which 200 are deadly. Continuous smoking leads to periodontal disease and gum disease. The smoke reaches your lungs when you inhale and gets exhaled through the mouth as well as nose allowing the chemical residues to reside in your mouth and airways and thus, comes out that unpleasant and unhealthy smell.

Periodontal disease refers to neglected oral hygiene. One major such disease is Halitosis. The bacteria formed plaque destroys the soft, delicate gum tissue. This bacteria also cause gum diseases, tooth decay and abscessed teeth.

This is a severe condition where the amount of saliva produced decreases, leading to a dry mouth. This dryness causes the trapped food to continuously rot and give out an unpleasant smell while exhaling. Saliva is very important to chew and swallow food properly. It is here where the primary digestion is initialized. Antihistamines, nasal sprays and anti-depressants can also dry up saliva. Xerostomia needs to be properly treated by a doctor.

When we forget to brush and floss regularly, the trapped food particles starts to decay in your mouth. The temperature inside mouth is 98.6 F which is favorable for decomposition of food and that is how the offensive odor emerges. Debentures if not cleaned regularly will give shelter to odor-causing bacteria and food particles.

The body metabolizes proteins and in doing so it produces ammonia. If the protein intake is too high then increased ammonia is present in their breath and urine gives the bad breath. Our body needs protein to build muscles and enzymes, therefore, we should not take excess of proteins.

When you are cutting carbohydrates in your diet and your body starts utilizing more fat for energy, Ketones are produced which contain acetone that tends to be excreted in urine as well as breath, thus giving the rotten apple smell. The good thing about ketones is that the smell does not stay forever. Drinking water, having natural mouth fresheners, gums minimize the bad breath.

Whatever we eat, it gets absorbed in our blood stream after digestion. This blood gets transferred to our lungs due to which the exact smell of the food you ate is exhaled from the mouth. Garlic, onion and spices are the most unpleasant odor producing ones. Even poor digestion can give similar results as the gases produced during digestion sometimes escape through your mouth releasing the odor it contains. Such gases are also produced from constipation and bowel disorders.