A system for preparing and dispensing a mixture of at least a first and a second substance comprising: i) a container for the first substance; ii) a closure cap of the container; iii) a capsule applied to a mouth of the container and comprising: - a containment chamber for the second substance; - a perforation means for perforating the chamber and said closure cap; said system taking on a rest configuration wherein the inside of the container and the inside of the containment chamber are fluid-dynamically separated and an operating configuration wherein said perforation means extends into the chamber and passes through the cap; iv) a mixture withdrawal mouth which is part of said said capsule; said withdrawal mouth being intended to dispense the mixture of the first and second substances outside the system; the chamber comprising: - a portion intended to be perforated by the perforation means; the portion being irreversibly perforable; - a bottom opposite the perforable portion; - an intermediate lateral side; the withdrawal mouth being afforded in a zone opposite the perforable portion; a movement of said chamber bringing about a passage from the rest configuration to the operating configuration; said perforation means comprising a conduit which in said operating configuration places the inside of the container in communication with the inside of the chamber; characterised in that said withdrawal mouth, in the rest configuration, is in fluid communication with the chamber; the capsule comprising an openable lid for closing the withdrawal mouth; the lid being located in a zone of the capsule opposite the container. i) a container for the first substance; ii) a closure cap of the container; iii) a capsule applied to a mouth of the container and comprising: - a containment chamber for the second substance; - a perforation means for perforating the chamber and said closure cap; said system taking on a rest configuration wherein the inside of the container and the inside of the containment chamber are fluid-dynamically separated and an operating configuration wherein said perforation means extends into the chamber and passes through the cap; - a containment chamber for the second substance; - a perforation means for perforating the chamber and said closure cap; said system taking on a rest configuration wherein the inside of the container and the inside of the containment chamber are fluid-dynamically separated and an operating configuration wherein said perforation means extends into the chamber and passes through the cap; iv) a mixture withdrawal mouth which is part of said said capsule; said withdrawal mouth being intended to dispense the mixture of the first and second substances outside the system; - a portion intended to be perforated by the perforation means; the portion being irreversibly perforable; - a bottom opposite the perforable portion; - an intermediate lateral side; the withdrawal mouth being afforded in a zone opposite the perforable portion; a movement of said chamber bringing about a passage from the rest configuration to the operating configuration; said perforation means comprising a conduit which in said operating configuration places the inside of the container in communication with the inside of the chamber; characterised in that said withdrawal mouth, in the rest configuration, is in fluid communication with the chamber; the capsule comprising an openable lid for closing the withdrawal mouth; the lid being located in a zone of the capsule opposite the container.