Halitosis ( bad breath ) can occur due to various reasons. Hence knowing the cause is very important so that the treatment can be done accordingly.
Few of the causes can be
Gastrointestinal Disturbances(GERDS)
Starvation/Fasting
Diabetes
Some patients develop bad breath when they have fever
One if the causes can also be poor oral hygiene and periodontal problems.
Visit a dentist to know your oral hygiene status, if required they will do the scaling( oral prophylaxis ).
If it is due to any other reason get treated accordingly.
Next Steps
After scaling follow the instructions given by your dentist such as brushing techniques, tongue cleaning, using suitable mouthwash ( if required) or flossing and maintain the same.
Health Tips
Knowing the cause is very essential in order to treat the problem. Visit your nearest dentist for opinion regarding oral hygiene status and proceed.