Joseph receives D&C 89 ["The Word of Wisdom"]. According to Brigham Young the School of the Prophets was meeting in Joseph's kitchen, a small room in the house attached to the store owned by Bishop Whitney. As the brethren would gather after breakfast, they would immediately light their pipes, filling the room with smoke, or they would begin to chew tobacco, spitting it on the floor. After the complaints of his wife, Joseph prayed about the problem and received the above revelation.
[Source: Journal of Discourses (26 volumes) 12:157-58; Conkling, Christopher J., Joseph Smith Chronology]