Yerba mate is an herb native to South America and is used to make the national drink of Argentina, Paraguay, Uraguay and Southern Brazil. In fact, yerba mate is consumed 6 to 1 over coffee in these countries. Along with tea, coffee, cacao, kola (or cola) and guarana, the yerba mate herb is used to produce a caffeinated beverage Yerba mate is an herbal tea made from the leaves and twigs of the Ilex paraguariensis plant. The leaves are typically dried over a fire, then steeped in hot water to make the tea. ... SUMMARY Yerba mate is a type of tea made from the dried leaves and twigs of the Ilex paraguariensis plant. The leaves are also sometimes used to make medicine. Some people take yerba mate for athletic performance, memory and thinking skills (cognitive function), fatigue, and many other purposes. But there is no good scientific evidence to support these uses. The yerba mate tree is a species of the holly family with leaves that are evergreen (showing leaves during all four seasons) and produce small fruit berries that flower into greenish white flowers. The leaves and tender stems are often hand picked then dried in a controlled environment. They are sometimes roasted over a wood fire before they may be broken or cut to create the final herb for consumption. Some yerba mate is even aged in cedar or other wood for up to a year or more for added flavor. Yerba mate has a slight astringent bitter taste due to the high tannin content of the leaves.