Liquid dispenser for discharging pharmaceutical liquid having a discharge head and a cap, the cap body of which has a ventilation opening. The dispenser includes an injection-moulded pull-off portion which, in the delivery state, covers the ventilation opening and is connected to the cap body by a substance-to-substance bond. The pull-off portion, together with a tamper-evident portion, which, with the dispenser in the delivery state, prevents removal of the cap body, is part of a common segment which is detachable from the cap body of the cap. Alternatively, the ventilation opening is provided with a filter membrane for filtering the air which flows through it, and the cap body includes two part-bodies which together form a receiving space for the filter membrane.