A medical valve assembly including a rigid external housing and a valve stem of a resilient material. The valve stem includes a passageway for conveying a fluid which has an hourglass shape to create a venturi effect when cleaning the valve stem to improve the efficiency of the cleaning process. The passageway also includes no sharp edges, thus reducing the risk of fluid getting trapped inside the passageway when the medical valve assembly is not in use. Even further, when a needleless syringe is removed from the valve stem, the valve stem expands to an uncompressed state with its top end being generally flush with an end of the housing to present a swabable surface for cleaning purposes.