A tamper proof container for pills, liquid medicines and other substances taken internally is formed of two molded components, fixed together after filling in a secure, permanently sealed bond. The first integrally molded component is an outer shell having a body portion, a neck portion and a closure or cap which may be in an inverted position on top of and closing off the neck portion, all molded together as one component. The second component is a bottom portion having a skirt or sides of substantial depth for fitting tightly in the body portion after filling. The bottom skirt and the body portion are closely fitted together, with a substantial area of contact between them, so that a large area of adhesion or heat bonding is possible, to the extent that the assembled container cannot be broken open without detection. Preferably, the walls of the skirt and the body portion are fully coextensive so that the assembled container appears as one piece. The plastic components may be transparent, permitting visual inspection, and there may be further included frangible low-profile fins on the outside of the outer container wall, to indicate if the container has been subjected to twisting forces as in the grip of a person's hand.