Black tea: Interactions with Herbs and Dietary Supplements
Studies of black tea
interactions with herbs and supplements are limited. However, black tea
is a source of caffeine for which multiple interactions have been documented.
There is controversy as to how black tea and caffeine affect blood clotting. Caution is advised when using herbs or supplements that affect blood clotting.
may increase the effects of herbs or supplements that cause the blood vessels to narrow (called vasoconstrictors).
may increase or decrease the effects of antidiabetic agents.