Susan,
As you probably know, deoderants contain aluminum, which is toxic if too much accumulates in the body (alzheimer's has been linked to excessive deposits of this metal in the brain). For this reason, I apply alcohol (Everclear) to my underarms and it works just as a deoderant would. I do not use any aluminum based deoderants. Health food stores sell supposedly a more healthful alternative to the drug store deoderants, a sort of crystal, but I don't believe it is any better as it is some sort of aluminum salt.
Perhaps, others here may provide their insight....