Cinnamon is a very familiar spice/herb to most people.  Often, I find that people are surprised to see it in cut bark form for use in a tea, however, as it is most familiar in powder form.  It has a long history of medicinal use and was shipped from the Spice Islands to Europe, the Middle East, Africa, India, and China in earlier times as part of the spice trade.  The inner bark of the Cinnamomum spp. is used and is transported in rolls.
A sweet, spicy, warming herb, I often use the bark in tea blends for its flavor and also because of its beneficial effect on blood sugar.  It increases insulin sensitivity of cells and can help decrease blood sugar spikes after a meal.  It is also a drying herb, so it can help decrease diarrhea and the associated fluid loss, as well as helping to slow or stop bleeding, and to help lessen mucus congestion of the lungs and sinuses.  A tincture (liquid extract) can be used to slow or stop postpartum hemorrhage.  It can also help with sluggish or weak digestion, especially when the stomach is cold.  One way to tell if someone has more of a “cold” digestive system is if they have a harder time digesting cold foods, such as raw vegetables and yogurt.  The tincture and oil are both very antimicrobial and antiparasitic.