Drink no wine or strong drink, you or your sons with you, when you go into the tent of meeting, lest you die. It shall be a statute forever throughout your generations.
#leviticus 10:9

No mind-altering drugs are allowed in priestly rituals. No alcohol, prozac, cannibis, or shrooms for the Cohen on duty. Although the command explicitly applies only to the sons of Aaron, I believe all leaders of corporate worship should follow this principle.
#shmini