Abstract: A folding carton is disclosed, preferably with a square cross-section when erected, having top and bottom forming members as well as front and rear and side members defining a square tube. Extending from one of the side members is a strut panel extending from one of the tubular forming panels, and having one extension strut and one reversely folded strut positioned thereon in spaced relationship. When the carton is erected, the two struts form a V-shaped type support, so that a triangular cross-section shaped bottle can be fitted within the carton, and secured against rotation. In the preferred embodiment, the front panel has an open window for displaying the label on the bottle. The bottom closure preferably is an automatic bottom, and positioned with the tug tabs adjacent the intersection of the strut panel and its adjacent panel so that when the carton is flattened, the two struts extend and are sandwiched in between the opposed pairs of panels.