In a dispenser, particularly an atomizer, which is used for flowable substances, particularly pharmaceuticals, use is made of a pump, which must be actuated one or more times for priming purposes. Its discharge nozzle (14) is covered by a protective cap (38), which is suitable to collect and store the medium, which is discharged during the priming strokes and before the start of the useful strokes. During the priming strokes the protective cap (38) is secured on the dispenser (11). This is brought about in that a locking (40) for the protective cap is only released when the priming strokes have been performed. This can take place by electrical actuation or by material change under the influence of the medium to be discharged. According to a variant the protective cap is not itself locked, but an actuation locking takes place if the protective cap has not been fitted for the priming strokes.