A medical port includes a main channel with a lumen to conduct a first fluid through the port, a secondary channel aperture of a secondary channel to add a second fluid in the main channel, at least one housing element and at least one actuation element arranged to be transferable relative to the housing element from a first position into a second position, a seal section, which is arranged to be rotatable between a first position of the seal section, in which the seal section does not close, seal or cover the secondary channel aperture and a second position of the seal section, in which the seal section closes, seals or covers the secondary channel aperture, when the actuation element is transferred from the first position to the second position. A blood hose including at least one port, and a medical treatment apparatus are also described.