You could be having a digestive problem, constipation could be a reason or Dental plaques .
Next Steps
Drink plenty of water.
Avoid caffeinated drinks- tea, coffee, coke etc, avoid getting constipated and If the problem still persists you will need to see a doctor to rule out any infection in your gut,
diabetes,
kidney problem
See a dentist. Dental plaque can cause bad breath and only a dentist on examination can tell you if you have plaque or not.
Check your blood
sugar, Fasting and
post prandial and Renal function test - Serum
creatinine
Meet your doctor with all the reports.
Health Tips
Take plenty of fresh fruits
Diet rich in fibre - beans, leafy vegetables
Drink water - 2.5 litrs at least.
Keep your mouth moist - dry mouth leads to bad breath.