Diphtheria morbidity among adult population of Moscow is growing. The tests of different modes and schemes of heterogeneous antidiphtheria serum administration have found out that the highest efficacy of serotherapy was achieved with a single intravenous dose. Another treatment of diphtheria is hemosorption. Widely used in present-day clinical practice hemosorbents provide adequate elimination of the toxin from plasma. The authors analyse the present situation in clinical symptoms, complications, lethality of diphtheria basing on the data provided by S. P. Botkin's Hospital.