I am a supervisor over the cashiers at our wal-mart and one of my cashiers has REALLY BAD breath to where I feel somewhat sick when she talks to me.

How do you tell someone they have possitively putrid breath without hurting their feelings?

No matter how gentle you are, it will still hurt her feeling but I'm sure she will appreciate your concern. Hopefully. When you do approach her, don't make it a long drawn out conversation. Say what you need to say, politely, and leave it alone. It will be up to her to take the proper steps. Either change toothpaste, use mouth wash, brush her tongue, have her teeth checked for infection or change eating habits.

Okay, so do "I" have bad breath??

Shawn - I don't envy your position -
But the customers may notice her breath too!
So you will certainly be justified if you choose to mention this to her.

If she chooses to take offense, you cannot help that. It is a problem that you, as manager (Oh joy!), need to address.

Good luck!