A molded collapsible solution container which container defines a chamber-defining body portion wall having an integral neck portion and shoulder portion at one end thereof. The container defines, in its normal, unstressed state, a transverse cross section which tapers from the shoulder portion progressively along a major portion of its length to a flat, sealed end portion at the end of the container opposite to the one end. In accordance with this invention, the shoulder portion is rectilinear in shape, with the wall circumferences of transverse cross sections preferably progressively decreasing in length along the container from adjacent the shoulder portion toward the opposite end. Opposed triangular gusset portions are preferably present in which the side of the gusset portion which is parallel to the shoulder edge is positioned directly against the shoulder edge, and the shoulder edge defines the shape of an enlarged, generally cylindrical section for ease of flexing. Flat areas are defined in the container wall between the gussets.