We estimated the effect of pentoxifylline (PTX) on the respiratory burst (examined by chemiluminescence method) of unprimed and primed neutrophils with tumor necrosis factor-alpha (TNF-alpha) in patients with stable angina pectoris. Chemiluminescence of non-stimulated as well as formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA) stimulated neutrophils was measured. We studied 45 patients with stable angina subjected to percutaneous transluminal coronary angioplasty (PTCA) procedure, who were randomly divided into two groups. The study group consisted of 24 patients who were administered pentoxifylline orally, and the control group consisted of 21 patients without pentoxifylline administration. Blood samples for examination were collected from the coronary sinus and peripheral vein just before the PTCA procedure. Pentoxifylline decreased the respiratory burst of non-stimulated and fMLP-stimulated neutrophils without affecting the chemiluminescence of PMA stimulated neutrophils. Moreover, pentoxifylline diminished the chemiluminescence non-stimulated and stimulated by fMLP but not by PMA of TNF-alpha primed neutrophils. We presume that administration of PTX in stable angina patients may have a beneficial effect.