Normothermic rabbits and rabbits with LPS induced fever were treated with chlormethine (Nitrogranulogen, Ntg) in the doses of 1 microgram/kg and 10 micrograms/kg. The blood was collected 4, 24, 48 hrs and 4, 7, 10 days after Ntg injection. Following indices of immunity were studied: T and B cells number, number of IgM producing cells after immunization with SRBC, serum IgG level, killing activity of neutrophils and number of phagocytized bacteria. It was observed that both doses of Ntg injected intravenously to normothermic rabbits, significantly increased the number of T and B lymphocytes and of IgM producing lymphocytes a well as the level of IgG in the serum, number of phagocytized bacteria and killing activity of neutrophils. Ntg in combination with LPS shortened the period of fever, and through the synergistic effect, significantly increased T lymphocytes number in the blood, IgG level in the serum, number of phagocytized bacteria and killing activity of neutrophils.