Abstract: A medical coupling has male and female members (1, 2) which push fit together, and a screw cap (7) which secures the members against separation. To prevent unintentional release of the cap, locking means, such as a ratchet and pawl mechanism, are provided between the cap and female member. An outer shell (25) can enclose the cap for providing an enclosure around the fluid connection to deter bacterial contamination. Alternatively a separate capsule can enclose the coupling for this purpose. The two members and cap are connectable by holding gripping portions which are located remotely from the parts forming the fluid connection to reduce risk of contamination. A valve system is associated with the female member for closing a flexible tube connected to this member and to displace liquid to fill the space left in this member when the male member is disconnected from it.