We studied the effects of ANAR containing antibodies to morphine in ultralow doses on immunological parameters in patients with opium abuse. Changes in blood content of immunocompetent CD3+, CD16+, and HLA-DR+ cells, lymphocytes carrying receptors for serotonin and dopamine, and humoral immune factors were evaluated. As differentiated from standard preparations, ANAR possessed immunomodulatory properties, increased the content of HLA-DR+ lymphocytes and immunoglobulins in the blood, and normalized the number of CD16+ cells.