Whats good for bad breath?

Oral hygiene. Good oral hygeine is the key. Brush, floss, mouthwash, dentitst.
Good oral hygiene! While acid reflux can be an issue, it is no longer considered a primary cause of bad breath. The major causes of non-food related breath odors (garlic etc.) are gum disease and rotting food particles on the tongue. Floss daily ; use a toothbrush w-toothpaste to brush as far back on your tongue as possible. (colgate total with antibacterial triclosan works great!) voila, no more bad breath!
Correct diagnosis. The question should really be what is the origin of bad breath? At least three reasons come to mind. 1.) periodontal disease (inflammation the gums) 2.) gerd (reflux of acid from the stomach into the upper airway. 3.) tonsillitis. The latter problem I have seen fairly often and the tonsils are small but often retain food particles in the crevices and really cause halitosis or bad breath.
Depends on cause. Some bad breath originates in the mouth other times the sinus or lungs. Garlic and onion is expelled by the lungs and no amount of mouthwash will eliminate that. Pungent breath may be related to chronic sinus issues and seeing an ENT would help. Gum disease can cause mouth related bad breath and one should see a dentist to have it evaluated.