At a 2010 conference for Mormon priesthood leaders in Colorado Springs, the first question asked was about the church’s policy on medical marijuana.
The response: It is an issue between the church member, the member’s bishop and the Lord, to be made in consultation with the scriptures and the LDS health code called the Word of Wisdom.
That last statement was made by Russell M. Nelson in a video leaked in 2016. Perhaps you’ve heard of him. Then he was a member of the Quorum of the Twelve Apostles; now he is president of The Church of Jesus Christ of Latter-day Saints.