Summary1) Results of immunosuppressive treatment in cases of autoimmune and immunological diseases are reported.2) The patients have been treated by 6-mercaptopurine (Purinethol) and chiefly by azathioprine (Imuran) during 2 to 26 months.3) There are 8 cases of systemic lupus erythematosus (S.L.E.), 3 cases of idiopathic autoimmune haemolytic anemia, 2 cases of periarteritis nodosa, 1 case of Schoenlein-Henoch disease, 1 case of erythrodermia.4) In S.L.E. cases, the treatment has improved subjective state of the patients, cutaneous, visceral and haematologic disorders. A decrease of the relapses frequency has been noted. However, there was only slight or no modification of inflammatory signs or serological state.5) Two out of 3 patients with haemolytic anemia were markedly improved.6) Cutaneous lesions observed in patients with periarteritis nodosa, Schoenlein-Henoch disease and erythrodermia quickly disappeared under immunosuppressive treatment.7) At the dosage used in this study immunosuppressive drugs seem to be effective on non-specific inflammatory reactions and chiefly on delayed allergic reactions rather than on humoral allergic manifestations.