The nociceptive flexion reflex (NFR) is a physiological, polysynaptic reflex allowing for painful stimuli to activate an appropriate withdrawal response. NFR is easily measurable in clinical setting, and is a reliable and objective tool for measurement of an individual's pain experience. An exhaustive review of the literature, covering multiple search engines, indicates that the NFR method is valuable in studying the impact of diverse pharmacological and non-pharmacological interventions on the flexion reflex, in conditions of acute pain and in healthy volunteers. More recently, the NFR method has gained particular attention as a research tool in studies of central sensitization and persistent or chronic pain.