We should not assume that medieval physicians did not take pains to found their practice upon evidence. Academic physicians at Montpellier ca. 1300 were cautious about accepting textbook claims for the powers of drugs, and tried to verify each drug's physiological effects before using it; yet they were also flexible, ready to believe that powerful new medicines might be discovered empirically that were unknown to their authorities or superficially inconsistent with existing knowledge. Likewise, physicians were careful to observe their patients closely and to try to identify the condition from which each was suffering, and when they were unsure of the nature of an illness, they feared to administer medicines lest their known effects might be harmful to the patient. Anticipating today's "evidence-based medicine," the physician's practice involved the conscientious use of current best evidence.