Smoking gives you bad breath.

吸烟会导致口臭。

《牛津词典》

His bad breath really grossed me out.

他的口臭实在使我恶心。

《牛津词典》

Have I got bad breath?

我有口臭吗？

《牛津词典》

You can say, "I told you that this gum makes your breath really bad."

你可以说，“我跟你说过这个口香糖会让你有难闻的口气的。”

I've been 课堂 - SpeakingMax英语口语达人

Let's say that you know that a specific chewing gum makes your breath bad.

假设你知道有一种口香糖会让你有不好闻的口气。

I've been 课堂 - SpeakingMax英语口语达人

For the food firms, gum that sweetens bad breath and whitens teeth is a hot market.

ECONOMIST: Medical confectionery

In our smothering proximity, we shared everything else snores and farts and bad breath and odorous feet.

NEWYORKER: Rat Beach

Finally, a pair of smartphone jackets bring some clever health tools, including the Bad Breath Analyzer -- our personal favorite.

ENGADGET: NTT DoCoMo bad breath, body fat and food analyzers hands-on (video)