(If you also have a sore mouth, sore gums, or a sore throat, talk to your doctor, nurse, or registered dietitian. They can suggest ways to help you without hurting the sore areas.) Choose and prepare foods that look and smell good to you.
1 Ravensara (R.aromatica) smells of a Cinnamon-Eucalyptus, and is also considered not as Therapeutic, but is used a lot for its Fragrance.  Ravintsara (Cinnamomum camphora) smells more of a Champhor-Eucalyptus, and is used when it is needed for Therapeutic purposes like respiratory help or shingles.
The smell depends on the type of gangrene. If the gangrene is caused by frostbite or lack of blood supply, the skin turns purple, and then to black. There is no smell initially. After a couple of days, the dead tissue (black sutff) starts to rot and smells like any dead animal would smell.