The invention relates to an extracorporeal blood treatment machine in which a blood circuit (3) is equipped with an inlet line leading to a filtration unit (2) and with an outlet line (3b) from the filtration unit; a fluid circuit comprises an inlet line (4a) leading to the filtration unit and an outlet line (4b) from the filtration unit so as to allow a fluid taken from a primary container (5) to circulate within the filtration unit, thus enabling the treatment of the patient's blood. There is further an infusion line (6) acting on the outlet line of the blood circuit, which is supplied by an auxiliary fluid container (7). The inlet line of the fluid circuit is equipped with at least an infusion branch (8) acting on the outlet line of the blood circuit so as to enable the intensive therapy machine to manage therapies with large exchange of fluids.