The valve (10) includes: a coupling housing (12) having an inverted T-shape configuration, with a first tubular segment (16) extending along a first axis (X) and forming at its opposite ends first and second connecting portions (20) for connection with a first, main line, and with a second tubular segment (18) extending along a second axis (Z) perpendicular to the first axis (X) and debouching into a middle portion of the first segment (16) a valve body (14) rotatably mounted in the second segment (18) of the housing (12) around the second axis (Z) between a first and a second position and a third connecting portion (28) for connection with a second, infusion line. The valve body (14) has an end portion (42) which is contained within the first tubular segment (16) of the housing (12) and defines a channel (44) arranged transversely with respect to the second axis (Z), in such a manner that when the valve body (14) is in the first position, the channel (44) is aligned with the first axis (X) thereby allowing fluid to flow along the main line through the first segment (16) of the coupling housing (12), and when the valve body (14) is in the second position, the channel (44) is arranged perpendicular to the first axis (X) thereby preventing fluid to flow along the main line through the first segment (16) of the coupling housing (12). The valve body (14) has a radial through hole (46) configured so as to connect the third connecting portion (28) with a downstream portion of the first segment (16) of the housing (12) when the valve body (14) is in the second position.
