I took 50mg of Zinc yesterday and didn't have bad breath for the first time in 20 years! Not sure if it was a fluke but I plan to try it again. Usually after I eat, I smell like rotted meat, my digestion must be off. I've tried every mouthwash on the market to no avail. I do take probiotics daily and they help but I think the Zinc did the trick.
Not all bad breath comes from the mouth, some people have a poor balance of intestinal flora which will cause you pass an unpleasant odor through your lungs. Also if you're not digesting food properly due to low stomach acid your breath will smell. Candida problems cause breath odor as well.
Zinc is worth a try though, inexpensive and easy to take!