Generation of active oxygen forms (AOF) in whole blood was studied in 63 patients with acute pneumonia and 72 asthmatics by chemiluminescence (CL) registration. CL intensity depended on the intensity of inflammatory process. Groups of patients with high and low blood CL were distinguished. In 35 patients intravascular laser exposure of the blood (ILEB) was added to therapeutic complexes. Disorders of free radical oxidation persisted for a long time in the majority of patients with high CL of the blood, treated by ILEB; in many cases the inflammatory process acquired a protracted pattern. By contrast, in patients with low intensity of blood CL, ILEB stimulated the generation of AOF and increased the treatment efficiency. Hence, whole blood CL can serve as a criterion of ILEB prescription and can be used for monitoring the patient's status during laser therapy.