Disclosed is a method for inhibiting Ras-induced or mediated proliferation of cells associated with a non-malignant disease, disorder or pathological condition. The method entails administering to a patient a Ras antagonist in an amount effective to inhibit the proliferation. The invention is particularly applicable to diseases characterized by a proliferation of T-cells such as autoimmune disease, e.g., type 1 diabetes, lupus and multiple sclerosis, and pathological states such as graft rejection induced by the presentation of a foreign antigen such as a graft in response to a disease condition (e.g., kidney failure). Other non-malignant diseases characterized by proliferations of cells include cirrhosis of the liver and restenosis. Preferred Ras antagonists are S-trans-trans farnesylthiosalicylic acid (FTS) and structurally related compounds (or analogs) thereof.