There are many things that cause bad breath, and chances are that you're familiar with many of them, including certain foods you eat, waking up to a dry mouth, and smoking.  All of these things can cause a temporary condition of bad breath and these cases usually go away after you brush or rinse.  However, there are some health conditions that cause bad breath on a more long-term basis, and often these cases cannot be corrected with a simple brushing of the teeth or rinsing with mouthwash.

Dehydration is one of the health conditions that cause bad breath.  Adequate moisture in the mouth helps rinse away germs and bacteria that cause bad breath.  A person can be dehydrated from simple factors such as living in a warm environment or from just not getting enough liquid in their diet.  However, some conditions that cause dehydration can also be health conditions that cause bad breath as a secondary symptom.  This might include kidney disease or diabetes.

Anything that affects the sinuses can be considered health conditions that cause bad breath.  Usually this means a person is breathing through their mouth more often, which causes bad breath by drying out the mouth.  While having blocked or plugged sinuses may not themselves cause bad breath, breathing through your mouth when you're sleeping or when you're just not aware of it certainly does.

Any practices that upset one's digestive system and metabolism are going to bring about health conditions that cause bad breath.  For instance, many who follow high protein diets report bad breath, as do those who fast on a regular basis.  These practices affect how the body is breaking down food and what food is being processed in the body, and this in turn produces stomach acids and other elements that bring about bad breath.

If you have excessively bad breath and have done everything you can to correct and control this problem, you would do well to schedule an appointment with a dentist or doctor.  There are many health conditions that cause bad breath that only your dentist or doctor can accurately determine, and it's best to get a proper diagnosis.  These may be related to hormone imbalances or problems with your metabolism.  There are also diseases of the gum and mouth that cause bad breath, so it's best to get these things checked out by a healthcare professional.