A dosing device for dispensing liquid from a container (1) in which flow through flow openings (23) to an outlet tube (44) is blocked after controlled delay by an obturator (3) moveable within a control chamber (2) mounted in a container neck (101) behind the outlet tube (44). Movement of the obturator (3) is governed by restricted flow through control openings (28) at the rear of the control chamber. Restoration of the obturator to the back of the control chamber facilitates repeated dosing. An elastomeric element (6) of resiliently deformable material promotes a seal to achieve a cleanly defined dose. In one proposal the elastomeric element coats the surface of the obturator and/or the outlet tube (64) to cut off the flow. Another proposal provides a one-way elastomeric valve element (63) for blocking the flow openings to enable rapid recovery after a dosing operation.