From The Encyclopedia of Mormonism
Author: Lyon, Joseph Lynn
Active Latter-day Saints abstain from drinking coffee. This practice derives from an 1833 revelation known as the Word of Wisdom, which states that "hot drinks are not for the body or the belly" (D&C 89:9). Hyrum Smith, Assistant President of the Church, later defined "hot drinks" as coffee and tea (T&S 3 [June 1, 1842]:800), establishing the official interpretation for subsequent generations. The Word of Wisdom was given originally to show the will of God, though not as a commandment. Abstinence from coffee has been expected of fully participating members since the early twentieth century (see Doctrine and Covenants: Section 89).
The main chemical in coffee that has caused health concerns is caffeine, a cerebral and cardiovascular stimulant. A large number of other substances are also found in coffee, and their effects on health are not yet well understood.
Gilman, A. G.; L. S. Goodman; and A. Gilman, eds. Goodman and Gilman's The Pharmacological Basis of Therapeutics, 6th ed., pp. 592-604. New York, 1980.
Stratton, Clifford J. "The Xanthines: Coffee, Cola, Cocoa, and Tea." BYU Studies 20 (Summer 1980):371-88.
JOSEPH LYNN LYON