Clinical and laboratory observations of alexithymia suggest that a neurophysiologic hypothesis may be more useful than the traditional psychodynamic explanations for understanding psychosomatic processes. Current data support the concept of a functional disconnection between the two cerebral hemispheres. A mechanism for this disconnection, based on Kaplan and Wogan's experimental analogue of alexithymia, is presented. This mechanism implicates an inability to process painful stimuli through right hemispheric processes as a causitive factor in psychosomatic illness. Discussion of how this mechanism explains clinical observations of psychosomatic illness, and suggestions for further studies to elucidate and test this hypothetical mechanism are presented.