The invention relates to a capsule comprising a hollow tubular body (2), a hollow cap (3) telescopically engageable on the body (2), the body (2) and the cap (3) defining an inner volume therebetween and being provided with complementary snap-fit means (12, 21) for locking the cap (3) on the body (2) in the fully closed final position, the complementary snap-fit means (12, 21) comprising a locking ring (12) formed on the body (2) and a complementary ridge member (21) formed on the cap (3), at least one air-vent (14) formed as an axial recess on the outer surface of the body (2) and suitable for ensuring fluid communication between the inner volume and the atmosphere. The capsule (1) is configured such that, in the fully closed final position, the inner surface of the cap (3) fits on the outer surface of the body (2) over a continuous circumferential contact section (33) and the air-vent (14) axially extends from the open end (5) of the body (2) toward the contact section (33), so as to provide fluid communication between the inner volume and the atmosphere over the whole range of engagement positions, excluding the fully closed final position wherein the inner surface of the cap (3) sealingly engages the outer surface of the body (2) over the contact section (33). Application to capsules for liquid dosages.L'invention porte sur une capsule comprenant un corps tubulaire creux (2), un capuchon creux (3) coopérant de façon télescopique sur le corps (2), le corps (2) et le capuchon (3) définissant un volume interne entre eux et comportant des moyens d'ajustement par serrage complémentaires (12, 21) pour verrouiller le capuchon (3) sur le corps (2) dans la position finale entièrement fermée, les moyens d'ajustement par serrage complémentaires (12, 21) comprenant un anneau de verrouillage (12) formé sur le corps (2) et un élément complémentaire (21) de saillie formé sur le capuchon (3), au moins une ouverture d'aération (14) constituée sous la forme d'un évidement axial s
