The Word of Wisdom (see Doctrine and Covenants 89) is a law of health for the physical and spiritual benefit of God’s children. It includes instruction about what foods are good for us and those substances to avoid.

Over time, Church leaders have provided additional instruction on those things that are encouraged or forbidden by the Word of Wisdom, and have taught that substances that are destructive, habit-forming or addictive should be avoided.

The article “Vaping, Coffee, Tea, and Marijuana” in the August 2019 issue of the New Era magazine states the following:

Green tea and black tea are both made from the leaves of the exact same tea plant. The only difference is that the leaves in black tea are fermented and in green tea they’re not. They’re both tea and against the Word of Wisdom. Some drinks have tea in them but don’t advertise that fact, so always check the ingredients. Also, iced tea is still tea.

Church leaders followed up with an official Statement on the Word of Wisdom, clarifying that green tea is prohibited by the Word of Wisdom.

Also see the section “Word of Wisdom and Healthy Practices” in the Church’s General Handbook (section 38.7.14).