Traditional tea is made from the plant Camellia sinensis. So no grains, wheat, barley, or rye are used in it's production. This includes all non-herbal teas like green, white, black, yellow, oolong, and pu-erh teas. Although no gluten is involved in these types of teas, they are all processed quite differently. That is why despite the fact that they all use the same plant, the taste, texture, smell, and caffeine amount is different. For herbal teas, that can be different. Although most herbal teas, including all 6 original Native American Herbal Tea blends, are gluten free, some tea companies will use gluten to get certain flavors to "stick" better. Often you will find this gluten flavoring in seasonal herbal teas that naturally cannot offer this type of taste or the flavoring just isn't strong enough.