BACKGROUND: Surgery cause alterations in immune and neuroendocrine responses. Cytokines and stress hormones are importanat mediators which modulate the various immune reactions. The aim of present study is to investigate whether clonidine premedication can affect on the concentrations of cytokines and stress hormones in abdominal hysterectomy patients. METHODS: Twenty two healthy women undergoing abdominal hysterectomy were randomly allocated to two groups: eleven control patients and eleven clonidine(0.15 mg) pretreated patients. Variations in blood cytokines, Interleukin-1beta(IL-1beta), IL-2, IL-6 and tumor necrosis factor-alpha(TNF-alpha), and stress hormones, cortisol and ACTH were studied. Blood sampling were conducted 4 times in each patient: after induction, after incision, after surgery 1 h and 3 h. Cytokines assays were carried out with commercially available ELISA kits, and cortisol with radioimmunoassay and ACTH with immunoradiometric assay. RESULTS: IL-1beta increased early and the concentrations of IL-1beta in clonidine treated group were significantly lower than control. The mean concentrations of IL-2 at 1 and 3 h after surgery were slightly higher than after induction in clonidine treated group. IL-6 increased significantly at 3 h after surgery in both groups. Clonidine lowered IL-6 during the whole period. TNF-alpha, and cortisol and ACTH concentraitons were not affected by clonidin. CONCLUSIONS: Clonidine pretreatment decreased IL-1beta and IL-6 concentrations, but not stress hormones in response to abdominal hysterectomy.