A connector for connecting a dialyzer to a fluid-carrying line is disclosed, wherein the connector includes a coupling portion, especially a male Hansen connector portion, for fluid-tight connection to a connector element, especially a female Hansen connector adapter, of the line. In a flow channel of the connector, a shut-off device is integrated, which below a predetermined pressure or when no fluid communication is provided between the dialyzer and the line shuts off the flow cross-section of the flow channel.
