This article summarizes numerous studies on the relationship of biological processes such as inflammation and thrombosis. The huge role of neutrophils and the extracellular neutrophil traps (NETs) secreted by them has been demonstrated. The discovery of NETs has opened new horizons in the understanding of neutrophil biology and the role of these cells in the body. The use of chromatin in combination with the intracellular proteins, as an effective antimicrobial agent has ancient roots and changes our understanding of chromatin only as a carrier of genetic information. Through NETs, neutrophils can contribute to the development of pathological venous and arterial thrombosis or immunothrombosis, as well as atherosclerosis. NETs release has been shown to be one of the causes of thrombosis in conditions such as sepsis and cancer. The presence of NETs in these diseases and conditions makes it possible to use them or individual components as potential biomarkers. NETs and their components may be attractive as therapeutic targets. Further studies of neutrophils and NETs are needed to develop new approaches to the diagnosis and treatment of inflammatory and thrombotic conditions. Perhaps long-forgotten drugs will find a new area for effective use.