The auxiliary doen ‘do’ in standard Dutch is usually described as ‘dummy’ because it supposedly adds nothing substantial to the meaning of the sentence. We argue, however, that the auxiliary does have a function in the sentence, as a marker of either habitual or intentional aspect. In an online production experiment, we investigated the acceptability of the allegedly dummy auxiliary doen ‘do’. Results show that the degree of acceptability of the auxiliary doen ‘do’ is very low, even lower than the widely disapproved use of hun ‘them’ as a subject in Dutch. However, because a significant difference was found in the acceptability between the habitual and the intentional reading, we conclude that the auxiliary doen ‘do’ in Dutch cannot be dummy, i.e. semantically empty.