The present study reports on a controlled investigation of 38 patients with signs and symptoms of presumed oral galvanism, referred to the Department of Oral and Maxillofacial Surgery of the University of Helsinki for examination and treatment. A significant difference in mental health and in intraoral sensitivity threshold was found between patients and controls: patients with oral galvanism were mentally more disturbed and had a lower sensibility threshold than those in the control group. There was no statistical difference in electrical currents, potential or energy capacity in the dental metallic restorations between patients and controls. The frequency of allergies and oral candida infection was similar to that of a normal population. The possibility of exposure to mercury was excluded through a head hair analysis. The psychic background of complaints and findings is emphasized and a hypothesis for the mechanism giving rise to discomfort is presented.