Abstract: The method enables a closure and security device having a screw stopper and a security capsule to be formed and applied to a container having an externally threaded circular mouth. The method includes: connecting to a stopper, a capsule forming foil as to provide the stopper with a skirt projecting by a determined portion from the free edge of the stopper, to obtain—a-stopper-skirt combination, applying the combination to the mouth of the container; and making the skirt rigid with the container, so as to obtain a stopper-capsule. The closure and security device includes a screw stopper, and a capsule which is rigid both with the screw stopper and with the adjacent part of the outer surface of the container.