Yerba Mate (pronounced YAIR-buh MAH-tay) is a drink that is very popular in South America, particularly Argentina and Uruguay. It is not actually a tea, but a type of holly. However, it is drunk much like tea. And like tea, it also contains caffeine.
In the Rioplatense area, people drink out of a dried gourd (called the “mate”), through a metal straw with a filter on the end (the “bombilla”) that goes into the gourd. The tea is called just “yerba” down there.
In Argentina, some people enjoy it with a little sugar. This never happens in Uruguay, however. The Uruguayans are more, what you might call “purists”. But in Uruguay you will always see people walking around with a big thermos under one arm, and the mate in hand. Uruguayans don’t like to go anywhere without their mate.
The drinking of mate is a very cultural thing, complete with unspoken rules. For example, when someone offers you mate, you drink some and then hand it back. If you say “thank you” when handing it back, then you are done drinking. If you do not, then you are still open to drinking some more and the exchange continues.
This very cultural event can only be fully experienced by visiting the countries of Uruguay or Argentina and drinking it with the local people. Be sure and brush up on your Spanish before leaving!