Many Mormons believe it is a violation of the Word of Wisdom to drink caffeinated drinks even though it does not specifically forbid them.
“What about cola drinks, kava, some health or sports drinks, or other drinks containing stimulants? An official statement by the Church’s leaders reads: ‘With reference to cola drinks, the Church has never officially taken a position on this matter, but the leaders of the Church have advised, and we do now specifically advise, against the use of any drink containing harmful habit-forming drugs under circumstances that would result in acquiring the habit. Any beverage that contains ingredients harmful to the body should be avoided’” (D&C Student Manual, p. 210).