Abstract: A cap with a safety opening system which includes an inside element (10) being screwed on the bottle neck, an outside cylindrical element (30) being coaxial to the inside element and a push-button (20) placed between the inside element and the outside one.When the push-button (20) is pressed toward the bottle, it interacts with the cogged rim (16) being present on the upper part of the inside element and it works as a transmission means between the outside element (30) being made to rotate in the cap untightening direction, and the inside element (10) being screwed on the neck of the bottle. When the pressure exerted by the push-button (20) stops, it is only possible to tighten the cap by rotating the outside element (30), said element being provided with a cogged rim (14) on its internal lateral surface (31) which engages with a corresponding cogged rim (13) being present on the external cylindrical surface of the inside element (10).