Use of sodium meta arsenite in the manufacture of an orally administered pharmaceutical composition for the treatment of tissue or organ rejection in a mammal. Use of sodium meta arsenite in an orally administered pharmaceutical composition for the treatment of tissue or organ rejection in a mammal. A kit comprising at least one therapeutically effective dosage amount of sodium meta arsenite, wherein the therapeutically effective amount of the arsenic compound is sufficient to cause suppression of host lymphocytes to alloantigen in a mammal that is the recipient of transplanted tissue or organ.
