Changes in the serum levels of immunoglobulin IgA, IgG, IgM, positive acute phase proteins and complement activity, as well as the lymphocyte subpopulations and the neutrophil leucocyte-related chemiluminescence in the blood of patients with apical granuloma as related to endodontic and surgical treatment were investigated. Measurements were performed on admission, and 7 days and 3 months after the treatment. Elevated IgM concentration, positive acute-phase protein levels and spontaneous whole-blood chemiluminescence were noted at admission. However, a significant decrease in the serum level of each of the six investigated acute-phase proteins, and in the spontaneous chemiluminescence of blood was observed during the 3-month follow-up period. The significant increase in serum complement activity following therapy suggests that complement fixation might have occurred in these patients. A significant increase in the ratio of early sheep erythrocyte rosette-forming lymphocytes was also observed. The results of this study provide evidence for complete recovery after elimination of local inflammation by proper endodontic treatment and apicectomy in patients with apical granuloma.