What should i do to get rid of bad breadth?

Cause: Would start with dental evaluation to determine if dental caries or gum disease is a cause. If not there are medical causes like sinusitis or gastric reflux disease that should be ruled out. Oral hygiene is a must and smoking is a significant cause. Take care.

Dental checkup.: When was the last time you had a dental checkup and cleaning. Brush your teeth, use a tongue scraper, mouth wash, better oral hygiene. However, if you did all of the above there might be a gastric problem. Without further info i can only guess that it's been a while since you saw a dentist.