SUMMARY The serum concentrations of zinc and copper were measured in 50 patients with multiple sclerosis. Lower serum zinc levels were found compared to age-and sex-matched controls. In younger patients low serum copper concentrations were noted. Zinc concentrations in CSF were unchanged. The possibility that malabsorption of the metals causes the low serum concentrations is discussed.In the search for the aetiology and pathogenesis of multiple sclerosis some interest has been expressed in the role of the trace elements zinc (Zn) and copper (Cu). Epidemiological data has shown a low prevalence of the disease in seacoast towns,' where the intake of seafood, rich in Zn, is high.2 Zinc and copper deficiency in some animal species may lead to hypomyelinisation.39 Conflicting reports of serum and plasma concentrations of Zn and Cu in multiple sclerosis have been published. Plasma Zn has been reported to be increased in 50 patients.'0 Decreased plasma Zn levels were reported by Wong et all" in 25 patients, 14 of whom had clinically definite multiple sclerosis. Serum Cu has been reported to be decreased,'2 or unchanged."'-6 In addition, serum albumin, which binds about 80% of the Zn in serum,'7 has been said to be decreased'8-20 or unchanged,'0 while the serum a2-macroglobulin, which binds about 20% of the Zn in serum, has been said to be depressed.'0 18-20 Transient elevations of several acute-phase reactants in serum, for example C3-pro-activator, C-reactive protein, orosomucoid and IgM, have been found during exacerbations of the disease.2'The aim of the present study was to correlate changes in the serum concentrations of Zn, Cu and albumin in multiple sclerosis patients with the age of the patients, the phase and duration of the disease, and the degree of disability. In addition the concentrations of CSF Zn were determined, and their relationship to the CSF proteins studied.