4. Bad breath
It’s no surprise that smokers have bad breath—and it’s not the kind you can zap with a quick breath mint. More than 4,000 chemicals pass through your oral cavity every time you smoke and many of them end up collecting on the surfaces inside your mouth. Smoking also contributes to bad breath by drying out your mouth, which can trigger gum infection and even irritate your sinuses, resulting in post-nasal drip.