i saw someone cured of gangrene with my own eyes by drinking lots of fresh wheatgrass juice. it was wildcrafted wheatgrass, grown in nature, he drank it by the cupful and his finger grew back perfect after the docs told him to cut it off.
also - CAYENNE. this is very powerful stuff and stimulates blood flow and circulation. the best on market is Dr. Schulzehttp://www.800herbdoc.com use it both internall and externally. rub it right into the wounds as much as she can handle. also internally as much as she can handle, start with small amount and keep increasing, if she wants to save her limb she can.
also any fresh (not bottled) juice will be good, carrot apple greens ect.