Does gangrene cause an odor?

It can: Gangrene means there is non viable tissue present. The odor usually comes from infection. The mere presence of non viable tissue does not immediately result in infection but over time, the possibility of infection increases and may result in an odor. If you are concerned whether there is non viable tissue present, do not wait for an odor, seek medical attention.

Yes: Often times the first indication that an gangrene has set in is that there is the unmistakable rotting odor. If you suspect this, you should be seen immediately in an emergency setting.