High Quality Content by WIKIPEDIA articles! A tea bag is a small, porous sealed bag containing tea leaves and used for brewing tea. Tea bags are commonly made of paper, silk or plastic. The bag contains the tea leaves while the tea is brewed, making it easier to dispose of the leaves, and performs the same function as a tea infuser. Some tea bags have an attached piece of string with a paper label at the top that assists in removing the bag while also identifying the variety of tea.