One of my favorite prepackaged teas is the Yogi Kava Blend. I say blend because it's not straight Kava tea--it's mixed with a variety of other roots and herbs. And honestly, that's something I do really love about some prepackaged teas. Instead of having to mix up your own blends and find all the specific, rare herbs you want to add, prepackaged tea bags do all the work for you.
This blend includes Carob Pods, Cinnamon Bark, Ginger Root, Cardamom Pods, Hazelnut, and more. In the end, it has a very full-bodied chocolate flavor to it, which I really love. Because if you're stressed out enough to be drinking Kava tea, you could probably use some chocolate as well.
So why Kava? Kava or Piper methysticum (Latin "pepper" + Latinized Greek "intoxicating") translates to intoxicating pepper. It has that name due to the substances it contains called kavalactones. Kavalactones affect your brain the same way alcohol does--making you feel relaxed and happy. This makes it a potent tea for nervousness and anxiety.
Native to the Pacific islands, Kava is used for medicinal, religious, political, cultural and social purposes throughout Hawaii, Fiji, Tonga, Vanuatu, Melanesia, and some parts of Micronesia.
One note about Kava is that it has psychoactive properties. Some witches therefore use it as a divinatory herb, to induce visions and ease astral projection. For this purpose, however, you would need a strong infusion (steeped overnight) or a fermented Kava drink.