“Du zhong” is often known as Eucommia Bark is a small tree that naturally grows in Southeast China. Mixed Herbal Tea Du Zhong Tea is blended with 10 kinds of tea such as Job’s Tears and Chinese Senna in addition to Du Zhong. A tea bag contains 3g of Du Zhong leaves, which is slowly roasted in a low-heat roasting process to bring out the flavor. No caffeine.