According to this unsubstantiated Wikipedia entry, criminals condemned to death by Beith Din were drugged and rendered senseless prior to being executed.
Is this factually correct (either Halachically or historically)?
אמר רב חסדא היוצא ליהרג משקין אותו קורט של לבונה בכוס של יין כדי שתטרף דעתו שנאמר (משלי לא) תנו שכר לאובד ויין למרי נפש
Said Rav Chisda: One being taken out to be executed, we give him a drink of a dose of frankincense dissolved in a cup of wine, to discombobulate his mind. As the verse (Proverbs 31) says, "give strong drink to one who is lost, and wine to the bitter of soul."
I don't think it was drugged to the point of unconsciousness, but some type of sedation.