There are two types of underarm products.  One type is deodorant -- with
lots of fancy "nice-smelling" ingredients to cover up the smell of the
bacteria that grow in sweat.  Some also include anti-bacterial ingredients
to actually prevent the bacteria from growing.

The other main type is anti-perspirant.  As the name implies, it prevents
you from sweating, therefore the bacteria have no moisture to grow in, so
they don't grow, so you don't stink.

Although these products are found on the same shelves at the store, they are
usually clearly labelled as one or the other, either "deodorant" or
"anti-perspirant."

Kathy D.