While the caffeine content of a cup of tea varies based on a number of factors, these herbal blends are caffeine-free. Per serving, the green tea blend has around 35mg and the black tea blend includes approximately 50mg. Newman's sells several varieties of its famous black tea, including Indian Black Tea, Chinese Black Tea and Sri Lankan Black Tea. All are flavored with white chocolate and spices such as cinnamon, nutmeg and allspice. The company also sells various green tea products that use the same recipe for its green tea powder and tea bags. Of all the varieties of black tea, Indian Black Tea has the lowest amount of caffeine per cup (35mg). Chinese Black Tea has about 50mg per cup and Sri Lankan Black Tea contains 75mg per cup. Caffeine is a stimulant that can cause headaches, jitteriness and insomnia at high doses. However, most people consume more caffeine than necessary to achieve these effects. Instead, the goal dose for most adults is 250-300mg per day, which is less than one cup of coffee or tea. For some individuals, though, a higher dose is needed to achieve the same effect. Women who are pregnant or trying to become pregnant should not consume any amount of caffeine since it can lead to premature contractions of the uterus.