Influence of reamberin on dynamics of functional condition of mitogen-induced immunocompetent blood cells at patients with widespread purulent peritonitis is studied. It is established that investigated immunocompetent cells have regulating effect on migration of neutrophil leukocytes at widespread purulent peritonitis during all postoperative period. PHA-activated mononuclear cells don't cause inhibition of migration of neutrophil granulocytes, observed in norm. At the same time the LPS-activated monocytes lead to migration strengthening of neutrophil granulocytes, in comparison with the data received in norm. Usage of reamberin at patients with widespread purulent peritonitis renders corrective action on immunocompetent cells, changing their properties of regulation of migratory activity of neutrophil granulocytes. The revealed effects at use of reamberin most expressed by the 7-10th days of the postoperative period.