Hermetically sealable container for liquids comprising: - a container body, delimiting the internal volume of the container laterally by means of a tubular container wall and underneath by a container bottom, from which said tubular container wall extends, said container body being provided with a mouth delimited by a free edge of said tubular wall; and - a cap, configured to close the mouth of the container body and make a hermetic seal therewith, wherein said cap comprises a main gripping body, which is intended to remain outside said container body, and a coupling appendage, which is intended to be inserted inside said container body through said mouth, extends axially between a base and a head end, and comprises a lateral coupling surface intended to face an inner surface of said tubular container wall, characterized in that the inner surface of said tubular container wall sequentially comprises starting from the free edge towards the bottom: - a conical guide surface converging towards the bottom; - an intermediate surface connecting said conical guide surface to a shoulder; - an end surface connecting said shoulder to the container bottom, wherein said intermediate surface defines a first annular prominence in proximity of said shoulder, in that the coupling appendage of said cap has an axial extension, so that the appendage may be inserted inside the container body until it reaches said shoulder with its head end, and has a radial extension at the head end, so that, once it has reached the shoulder, the head end abuts against said shoulder, so as to create a first sealing area between the cap and container body, in that the head end portion of the coupling appendage is radially dimensioned such that, when the head end abuts on said shoulder, the head end portion interferes with said first annular prominence, creating a second sealing zone between the cap and container body, and in that the coupling appendage of said cap comprises a second annular prominence which projects from said lateral coupling surface in proximity of the base of said coupling appendage and is axially positioned so that, when the head end abuts on said shoulder, said second annular prominence interferes with the conical guide surface, creating a third sealing zone between the cap and container body. - a container body, delimiting the internal volume of the container laterally by means of a tubular container wall and underneath by a container bottom, from which said tubular container wall extends, said container body being provided with a mouth delimited by a free edge of said tubular wall; and - a cap, configured to close the mouth of the container body and make a hermetic seal therewith, wherein said cap comprises a main gripping body, which is intended to remain outside said container body, and a coupling appendage, which is intended to be inserted inside said container body through said mouth, extends axially between a base and a head end, and comprises a lateral coupling surface intended to face an inner surface of said tubular container wall, characterized in that the inner surface of said tubular container wall sequentially comprises starting from the free edge towards the bottom: - a conical guide surface converging towards the bottom; - an intermediate surface connecting said conical guide surface to a shoulder; - an end surface connecting said shoulder to the container bottom, wherein said intermediate surface defines a first annular prominence in proximity of said shoulder, - a conical guide surface converging towards the bottom; - an intermediate surface connecting said conical guide surface to a shoulder; - an end surface connecting said shoulder to the container bottom, wherein said intermediate surface defines a first annular prominence in proximity of said shoulder, in that the coupling appendage of said cap has an axial extension, so that the appendage may be inserted inside the container body until it reaches said shoulder with its head end, and has a radial extension at the head end, so that, once it has reached the shoulder, the head end abuts against said shoulder, so as to create a first sealing area between the cap and container body, in that the head end portion of the coupling appendage is radially dimensioned such that, when the head end abuts on said shoulder, the head end portion interferes with said first annular prominence, creating a second sealing zone between the cap and container body, and in that the coupling appendage of said cap comprises a second annular prominence which projects from said lateral coupling surface in proximity of the base of said coupling appendage and is axially positioned so that, when the head end abuts on said shoulder, said second annular prominence interferes with the conical guide surface, creating a third sealing zone between the cap and container body.