In this study was compared the mental health status of 47 multiple sclerosis patients with silver/mercury tooth fillings (amalgams) to that of 50 patients with their fillings removed. On the Beck Depression Inventory the multiple sclerosis subjects with amalgams suffered significantly more depression while their scores on the State-Trait Anger Expression Inventory indicated the former group also exhibited significantly more anger. On the SCL-90 Revised, subjects with amalgam fillings had significantly more symptoms of depression, hostility, psychotism, and were more obsessive-compulsive than the patients with such fillings removed. On a questionnaire containing 18 mental health symptoms multiple sclerosis subjects with amalgam fillings reported a history of 43% more symptoms than those without amalgam fillings over the past 12 months. These data suggested that the poorer mental health status exhibited by multiple sclerosis subjects with dental amalgam fillings may be associated with mercury toxicity from the amalgam.