An aspirator (1) comprising an elongated housing (2), a piston member (3) and a grip (15a,15b) protruding through at least one slot (9a,9b) of a circumferential wall of the housing (2) for moving the piston member (3) axially to adjust aspiration pressure, and an end closure (5) for confining the piston member (3) inside the housing (2). The aspirator has a suction end (7) partly closed by an annular end wall (11) inclining inside the housing (2) and encircling the suction opening (16) to form a contact surface against the skin that enables fast and effective sealing during retraction of the piston member to create a negative pressure.