Safety device (10) for the safe administration of fluids through luer and non-luer connections, characterized in that it has two pieces (20) and (40) connected to each other by non-luer connections (30) and (50) with threads (31) (32) (53), the first piece being formed by a proximal female luer connection (60) and a distal non-male luer connection (30), and the second piece (40) by a proximal non-female luer connection (50) and a distal male luer connection (70), the luer connections having safety mechanisms formed by a cylindrical fitting (21) and (41) with a lid (22) and (42) in the form of a sectioned crown, which are closed permanently thanks to a slot with a triangular section inside the cylindrical fitting (25) and (45) in which a projection with a triangular section of the cover (24) and (44) is fitted, having provided that inside of the connection (21) and (41) closed by the cover (22) and (42) the luer connections of serum systems are coupled therapy, infusion sets, or catheters. (Machine-translation by Google Translate, not legally binding)