Long-term high-dosage penicillamine treatment of patients with advanced stages of diseases with autoimmune components has resulted in very few adverse reactions in a series of over 50 such patients also given selected nutrients: pyridoxine, zinc and magnesium (which penicillamine inactivates or chelates), and vitamins B1, B12, and E (which have sulfhydryl-protective activity). The patients on this regimen have been essentially free of the side effects that occur in about a third of patients treated with penicillamine without such supplements. Reports of myasthenia gravis—a disease with abnormalities of the thymus and of T-cells, as a side effect of penicillamine—suggest that zinc, magnesium, and pyridoxine might be the agents most likely to be protective. Pyridoxine is necessary for cellular accumulation of zinc and magnesium, deficiencies of which have caused thymic and other immunologic abnormalities. Whether the other vitamins administered contribute to the favorable results requires further study.