Non-specific immunosuppressive therapy of man is associated with considerable morbidity. Some regimens may be superior to others. The New Zealand mice offer a convenient model for studying different drug regimens prior to study in patients. Soluble suppressor substances have prolonged life in NZB/NZW mice. Treatment of NZB/NZW mice with Ribavirin, a broad spectrum antiviral drug, has been very effective. Renal deposits of immune complexes can be prevented. Such treatment is potentially applicable to humans with SLE. Male sex hormones, testosterone and 5 alpha-dihydrotestosterone (but not Danazol) prolonged life in female NZB/NZW mice. Such treatment was effective even when started after clinical illness and did not require castration for its full effect.