It is the national drink in Uruguay, Argentina, Paraguay, etc. Mate is served with a metal straw, is called a bombilla. Mate is an infusion, prepared with yerba mate and hot water.
Mate is traditionally drunk in a particular social setting, with friends. One person "the cebador" assumes the task of the server. "The cebador" fills the mate and drinks the mate firs to ensure that it is good quality.
The drink taste like a cross between green tea and coffee, with hints of other herbs, like mint, etc. Some drinkers takes it bitter "mate amargo", others add sugar, creating "mate dulce". Other very common variations are adding cold orange juice, lemonade, etc, called "tereré".