The role of angiogenesis in the development of neoplasia has been identified and characterized. However, antiangiogenic therapeutic intervention still requires more evidence to become recognized and successful. The aim of this study was to evaluate levels of selected proangiogenic factors, such as fibrinogen, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in serum of patients with the gynecologic cancer on the first, third and sixth day of antibiotic therapy, routinely administered as a perioperative treatment. In addition, serum concentrations of gamma-gamma dimers and alpha-polymers of cross-linked fibrin structure and the degree of bFGF binding with the fibrin network were investigated. Immunohistochemistry staining of the excised tumor tissue was also performed. We observed higher levels of bFGF, VEGF, as well as fibrinogen in patients with gynecologic malignancy, as compared to healthy women. In cancer patients, the concentration of alpha-polymers and gamma-gamma dimers of fibrin network increased. Further only gamma-gamma dimers fraction of fibrin was found to bind to bFGF. Immunohistochemical analysis indicated the presence of bFGF in an excised tumor tissue. In conclusion, the decrease of proangiogenic bFGF and fibrinogen levels in a clinical trial of gynecologic patients may confirm anti-angiogenic properties of selected antibiotic therapy.