Oral administration of the amino acid histidine to six patients with progressive systemic sclerosis produced anorexia, taste ans smell dysfunction, changes in mentation, and cerebellar dysfunction in each patient; these changes were associated with significant decreases in serum zinc concentration and significant increases in urinary zinc excretion. Administration of zinc ion, even with continued histidine administration, returned each of the signs and symptoms to or toward normal within 8 to 24 hours in each patient at the same time that correction of the serum zinc concentration occurred. The signs and symptoms noted constitute a syndrome related to acute zinc loss.