Let's be realistic here.
Mouth odour or bad breath is very embarrassing and wicked.
Wicked to the people sitting close to you, cause you are making them uncomfortable and they really can't complain cause they don't want to embarrass you.
It is caused as a result of a whole lot of things, they include: dental cavities, gum disease, poor oral hygiene, coated tongue (a white or yellow coating on the tongue, usually due to inflammation), mouth sores and other reasons.
There are many reasons as to what to do to overcome this, different people with various perception that might now work for you.
The best and natural form of way is to eat vegetables and fruits especially unriped Guava. As strange or funny as its sounds, that's the best natural remedy for mouth odour. Unriped Guava has its way of cleaning the mouth and eradicating bad breath as quickly as it can. Even if you don't have mouth odour, it also improves your breath purity.
Give it a try and recommend it to people with mouth odour, lol. Recommend it indirectly o, so they wouldn't slap you!
If you wanna know the medical way to get read of mouth odour, click here but this will definately do.