In many people, they are the primary causes of bad breath. Smoking or chewing tobacco-based products can also cause bad breath, stain teeth, reduce your ability to taste foods .Poor oral hygiene leads to bad breath because when you leave food particles in your mouth, these pieces of food can rot and start to smell. Maintaining proper oral health can help reduce or eliminate bad breath.

Gum disease caused by plaque and tartar can also cause bad breath. A bad stomach can also cause bad breath. The medical condition dry mouth which is also called xerostomia can also cause bad breath.

Diseases Diabetes, gastroesophageal reflux disease (GERD), liver or kidney disease, lactose intolerance etc can also cause Bad breath. Dirty dentures, false teeth and other fixed appliances in the mouth may also responsible for causing bad breath.

• Tobacco causes its own form of bad breath. Smoking affects; oral hygiene is a common cause of bad breath, which causes gum disease.
• Foods and drinks, such as garlic, onions, cheese, orange juice, and soda are also the cause of bad breath.
• Small food particles taken in between the meal are also responsible for bad smell.
• Bits of food that get caught between the teeth and on the tongue will rot and can cause your breath bad.
• Poor dental hygiene is also another factor, which is responsible for bad breath.
• Diabetes can also cause ketosis, and which too result in bad breath.
• Correct and regular brushing is very important to keep your breath smelling fresh.
• Infections in the throat, nose or lungs; sinusitis; diabetes; or liver or kidney problems are also the causes of bad breath.
• Another cause of bad breath is a condition called xerostomia, or dry mouth. Dry mouth favors bacterial activity. Any condition which produces dryness in the mouth makes the bad breath.
• There are several medical conditions, which can cause bad breath, in which respiratory diseases is important one.