Why does my bellybutton have an odor?

Many suffer from foul odor from body folds—the belly button is an area containing small folds within that may emit a foul odor.

Skin Infections:

Bacteria and yeast may live within these small folds and release chemicals that are responsible for the body odor. Staphyloccocus and streptococcus bacteria are among the most common bacteria skin infections overall.