A system for preparing beverages, comprising a capsule (2) containing at least one powdered food substance that can be extracted by pressing water through it to prepare a beverage, the capsule (2) comprising a substantially cup-shaped body (3) having a central axis (4), the body (3) comprising a bottom wall (5), a side wall (6) extending from the bottom wall (5) and, in the end of the side wall (6) opposite the bottom wall (5), a perimeter edge (7) protruding out of the side wall (6), the capsule (2) also comprising a cover (8) associated with the perimeter edge (7) to close the upper part of the body (3)； a capsule holder (9) forming a housing (10) therein to accommodate the capsule (2), the capsule holder (9) comprising a feed opening (11) through which the capsule (2) can be inserted into the housing (10), the feeding opening (11) being bounded in its perimeter by an annular edge (12) of the capsule holder (9), in whose upper part there is a protruding annular element (19) and / or, respectively, a ring seat (20)； injection means (14), mounted on the capsule holder (9), to inject, in practice, pressurized water into the capsule (2) through the bottom wall (5)； collection means (15) to collect, in practice, the beverage distributed through the cap (8) of the capsule (2)； existing on the perimeter edge (7), on the opposite side to which the cap (8) of the capsule (2) is associated, an annular groove (21), on whose surface there are three parts arranged annularly relative to the axis central (4), which consist of a lower zone (23) and two inner lateral faces (24, 25) that are located laterally on opposite sides of the lower zone (23), and / or existing, respectively, an annular tooth ( 22), on whose surface there are three annularly arranged parts relative to the central axis (4), which consist of a pointed part (29) and two outer lateral faces (30, 31) that are located laterally on opposite sides of the pointed part (29)； the capsule holder (9) and the capsule (2)
