Anesthesia at medieval medicine

This is not to say that anesthesia was not attempted in the medieval times. Many potions were known to a medieval surgeon which were to be used during surgery. Some of the potions used to relieve pain or induce sleep during the surgery were themselves potentially lethal. For example, one of these consisted of lettuce, gall from a castrated boar, bryony, opium, henbane, and hemlock juice - the hemlock juice could easily have caused death.
More of this topic can be found at :
http://www.oldpreparation.com/medieval medicine.htm