Abstract: Inactivated staphylococcal alpha toxin which is in a detoxified immunogenically active form prepared as a vaccine and administered parenterally to patients having multiple sclerosis or other disease involving demyelination of nerve sheath myelin. The amount of the inactivated alpha toxin administered is sufficient to effectively immunize the patient against active staphylococcal alpha toxin. The patient becomes subsequently infected with staphylococcus, the alpha toxin resulting from the infection is neutralized by the alpha toxin binding antibodies. This prevents exacerbation of the demyelination of the nerve sheaths, which otherwise can be promoted by the alpha toxin resulting from the staphylococcus infection.