A 31-year-old black man was examined for evaluation of a suspected occupational disease. Three years earlier he had been suffering from acute mercury intoxication during work in a mercury recycling factory. Skin symptoms then had been a lichenoid drug eruption, patchy alopecia and stomatitis, which had all disappeared rapidly after systemic glucocorticosteroid treatment. The examination revealed positive patch test reactions to metallic mercury and inorganic mercury compounds, an elevated titre of serum antinuclear antibodies and normal IgE levels. The induction of antinuclear antibodies by mercury has been shown in animal experiments. It can be hypothesized that this patient, who may have had an increased individual susceptibility, became allergic to mercury by the mercury intoxication.