A tea bag is a small, porous sealed bag containing tea leaves and used for brewing tea, or herbs or spices for brewing tisanes. 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.
In countries where the use of loose tea leaves is more prevalent, the term tea bag is commonly used to describe paper or foil packaging for loose leaves. They are usually square or rectangular envelopes with the brand name, flavour and decorative patterns printed on them.