A safety capsule for containers, comprising: an external cap; an internal element, located inside the external cap and configured to be associated, in a removable manner, with an opening of the container; a coupling means, configured to enable coupling of the external cap or the internal element to the neck of the container; connecting means (4, 5), interposed between the external cap and the internal element, and structured so as to leave the external cap and the internal element unconstrained with respect to a movement for opening or removal of the external cap between a closed position and an intermediate position, and solidly constrain the external cap and the internal element with respect to the movement for opening or removal of the external cap between the intermediate position and an opening position; the coupling means for coupling the external cap or the internal element and the neck of the container provides for at least one rotation movement about a longitudinal axis for the opening or the removal of the external cap from the neck of the container; the connecting means (4, 5) comprise at least a first connecting element, solidly constrained to the external cap, and at least a second connecting element, solidly constrained to the internal element; the internal element comprising a projecting edge of a substantially annular shape and concentric with the longitudinal axis, for constraining the internal element to the external cap with respect to movements along the longitudinal axis, the first connecting element comprising a small tooth (41, 42) that projects radially from an inner surface of the external cap and faces the internal element; the second connecting element comprising a first small tooth that projects from an external surface of the internal element and faces the external cap; characterized in that the small tooth (41, 42) projects beneath the projecting edge of the internal element, so as to prevent the internal element from sliding off the external cap, and that the first small tooth, projecting downwards parallel to the longitudinal axis, is associated with the projecting edge of the internal element. an external cap; an internal element, located inside the external cap and configured to be associated, in a removable manner, with an opening of the container; a coupling means, configured to enable coupling of the external cap or the internal element to the neck of the container; connecting means (4, 5), interposed between the external cap and the internal element, and structured so as to leave the external cap and the internal element unconstrained with respect to a movement for opening or removal of the external cap between a closed position and an intermediate position, and solidly constrain the external cap and the internal element with respect to the movement for opening or removal of the external cap between the intermediate position and an opening position; the coupling means for coupling the external cap or the internal element and the neck of the container provides for at least one rotation movement about a longitudinal axis for the opening or the removal of the external cap from the neck of the container; the connecting means (4, 5) comprise at least a first connecting element, solidly constrained to the external cap, and at least a second connecting element, solidly constrained to the internal element; the internal element comprising a projecting edge of a substantially annular shape and concentric with the longitudinal axis, for constraining the internal element to the external cap with respect to movements along the longitudinal axis, the first connecting element comprising a small tooth (41, 42) that projects radially from an inner surface of the external cap and faces the internal element; the second connecting element comprising a first small tooth that projects from an external surface of the internal element and faces the external cap;