Immunothrombosis is a normal physiological phenomenon against harmful pathogens that can limit their further spread. It is an important element of the intravascular innate immune system and performs at least four different physiological functions: it helps to capture and localize pathogens; it prevents the invasion of pathogens into tissues by microthrombosis; it contributes to the destruction of pathogens; it helps to recruit additional immune cells to the site of tissue infection and/or damage. The main driving forces of immunothrombosis are platelets, neutrophils and the complement system. This review examines the role of immunothrombosis in protecting the host and its main mechanisms.