The Word of Wisdom 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.

In recent publications for Church members, Church leaders have clarified that several substances are prohibited by the Word of Wisdom, including vaping or e-cigarettes, green tea, and coffee-based products. They also have cautioned that substances such as marijuana and opioids should be used only for medicinal purposes as prescribed by a competent physician.