Yerba mate is a herb used to make a caffeinated beverage, which can be served both, hot and cold. The drink made from this herb when served cold is known as tererÃ© in GuaranÃ. People in China, Bolivia, Brazil, Argentina and Paraguay consume this beverage. It is also often added to several energy drinks and can be found being sold as packaged iced tea. The traditional preparation of Yerba Mate involves the use of a gourd, which is a container, and yerba, which is placed inside the gourd. The gerb is either crushed or ground, followed by adding of water into the gourd. When hot water is added, herbs infuse into the water quickly.