Halitosis is just a fancy word for bad breath. It can be caused by not brushing your teeth, of course, but even those who brush their teeth regularly may have halitosis. Why? Gum disease (gingivitis), tooth decay, smoking, dieting, ketosis, eating stinky foods like garlic or fish (chewing on parsley can help), or a digestive "upset". Halitosis could be an indicator of lung or sinus infection or cirrhosis of the liver, and infoplease.com informs me that "the minty odour of acetone on the breath is a symptom of diabetes mellitus". (And here I thought acetone was paint thinner, which no one would call minty smelling.)
Got halitosis? Brush your teeth, use mouthwash, sure, but these will mask, not cure, bad breath. You may have to see your dentist or doctor to take care of it permanently.