Abstract: A flexible, flat-collapsible bag containing parenteral solution may be adapted for aseptically receiving and mixing the contents of another container, with the flat-collapsible bag preferably initially containing, prior to receiving said contents, a liquid for parenteral administration in a volume of 30 to 70 percent of the holding capacity of said flat-collapsible bag. The bag defines at least a pair of access ports, one of the ports being sealingly connected to flexible, crimpable, thermoplastic tubing of a length of at least 11/2 inches, and a sealed connector member carried on the outer end of the flexible thermoplastic tubing, in which the seal connector member defines a sleeve including a sealing diaphragm in the bore thereof, with the sleeve constituting an extension of the flexible thermoplastic tubing. Accordingly, a piercing spike may sealingly enter the sleeve to rupture the diaphragm.