A cap for closing containers includes a dispenser placed in connection with the interior of a container for dispensing a fluid contained in the container, a first sleeve integral with the dispenser and able to be screwed on the neck of the container to make the dispenser integral with the container. The cap further includes a second sleeve coaxial and surrounding the first sleeve and coupling elements active between the first and the second sleeve to couple mechanically the second sleeve to the first sleeve during a rotation of the second sleeve (7) in a first direction and to uncouple the second sleeve from the first sleeve during a rotation of the second sleeve in a second direction, opposite to the first. A covering element encompasses the dispenser and can be uncoupled from the cap coordinating a sequence of operations on the cap.