Why does my mom have such bad breath?

When I would remove Mom's teeth to brush and then soak them, I would have her do a rinse and spit with mouthwash. This worked until she forgot how to rinse and spit and would swallow, then I used water. This kept her breath fresh. Even dentures can get an odor from trapped food and saliva. You really do need to soak them daily if you haven't been.

You could ask a dentist or her MD to check for some kind of infection. Bad breath can be just from what she ate, too.

My aunt was severely constipated due to too much thyroid medication. We didn't know what was wrong. She said she was having bowel movements but when her aid told me her breath smelled like poop, I took her to the ER. She had other symptoms besides bad breath. Her bp was going up, she seemed depressed, wanted to stay in bed. Wasn't really eating that well but wasn't losing weight. We had been trying antidepressants, supplements and anything we could think of. After X-rays it was confirmed she was full of poop. Once we got it out the symptoms went away. So, your mom may not be full of poop but that will really cause bad breath. Her nurse was hearing bowel sounds etc but regardless that was her problem. The bad breath was the symptom that helped us figure it out. By the way, she has dentures also.