The effect of the novel agent gamma-(2-aminoethylamino)-2-butyrothienone (gamma-ABT) on local and systemic changes of rats with adjuvant induced disease (AID) was investigated, gamma-ABT showed potent inhibitory effect on adjuvant primary inflammation and almost totally inhibited the secondary lesions. gamma-ABT improved the changes in lymphoid organ weight except of the thymus. gamma-ABT improved the change in albumin/globulin ratio, which is a parameter of systemic inflammatory reaction but did not improve the body weight gain in AID and normal rats. In addition gamma-ABT did not affect directly T or B lymphocytes as shown by the lymphocyte responses to mitogen (Con A) and a T cell dependent antigen (SRBC) but rather inhibited the suppressor cells found in AID. Although structurally gamma-ABT is completely different from known non-steroidal anti-inflammatories, immunosuppressive drugs behave to a great extent like them.