The relationship between the group B Coxsackieviruses and a wide variety of illnesses, particularly pleurodynia and myo/pericarditis, is already well established. The detection of raised levels of neutralizing antibody to these viruses in a group of patients in a rural practice presenting with an illness resembling myalgic encephalomyelitis (ME) was therefore unexpected. This is a most distressing and debilitating illness for the patient and the affected family. What is the immunological failure in these patients which apparently allows this virus to persist causing such unusual and bizarre illness? At present ME is probably much commoner than is realized, the majority of patients being given the dismissive diagnosis of psychoneurosis.