Closed pouch comprising a wall defining an enclosed space containing carbon dioxide, and a pair of syringes contained within the enclosed space. The syringes are connected together by a syringe connector, and of the syringes contains a gas or gas mixture other than air, while the other contains a foamable liquid. Breakage of the syringe, connector and pumping of the syringes produces a foam useful in the treatment of varicose veins.