A valve for use with a container having intravenous liquid therein, the valve including: a valve body including a valve chamber formed therein an inlet in fluid communication with the valve chamber means for connecting the inlet, in use, to the container so that liquid can flow through the inlet to said valve chamber an outlet having means for connection, in use, to a catheter for intravenous delivery of the liquid the outlet including an outlet port which opens to said chamber, the port being surrounded by a valve seat a diaphragm mounting means for mounting the diaphragm to the body so that a peripheral edge or edge region sealingly engages the body and closes said chamber and such that the diaphragm sealingly engages the valve seat the arrangement being such that, in use, the head of liquid within the container unseats the diaphragm from the valve seat so that the liquid flows to said outlet but when the level of liquid in the container falls to a predetermined level the diaphragm sealingly engages the valve seat to stop further flow of liquid to the outlet.
