Patients with FM have a problem with central pain processing. The exact causality of the heightened pain sensitivity in FM is poorly understood. What is generally agreed is that the central sensitization seen in FM is secondary to a combination of genetic and environmental factors that render the patient susceptible to developing the widespread chronic pain and related symptoms seen in FM. We believe that, when FM patients are exposed to significant life stressors, be they physical or emotional, it results in an abnormal stress which activates herpes virus mediated-immune response. Herpes viruses are unique in that they remain in a dormant state (latency) in neuronal nuclei as nonintegrated, circular DNA associated with nucleosomes, with recurrent reactivations for the life of the host (as seen below). We believe it is likely that nerve resident viral herpetic reactivation is necessary for the waxing and waning nociceptive manifestation of FM. This cyclical process of virus reactivation and lytic infection of HSV-1 is postulated to perpetuate FM symptoms in these patients.