3,971. Ruling Under the Influence

Hilchos Bias HaMikdash 1:2

If a kohein is intoxicated from something other than wine, he may not enter the Temple. If he enters and performs the service while drunk from something other than wine, he is subject to the penalty of lashes; this is true even if one is intoxicated from milk or figs (which can make one drowsy in large amounts). Nevertheless, the service that he performed is valid. This is because someone is only subject to a Divine death penalty for drinking wine at the time of service, and one’s service is only disqualified for being drunk from wine.

Hilchos Bias HaMikdash 1:3

Just like a kohein may not enter the Temple intoxicated, it is equally prohibited for anyone – kohein or Yisroel – to rule in a matter of halacha when drunk. Even if one only ate dates or drank milk, making his mind a little confused, he may not rule in a matter of halacha, as per Leviticus 10:11: “…and to instruct the children of Israel.” It is permitted to give a ruling that is so explicit in the Torah that even the Sadducees (who rejected the Oral Law) know it. For example, if one ruled that one of the eight sheratzim is ritually unclean, that a frog is ritually clean, that eating blood is prohibited, etc.