We investigated whether speakers can use an internal channel to monitor their speech for taboo utterances and prevent these from being spoken aloud. Therefore event-related potentials were measured while participants carried out the SLIP task. In this task, speech errors were elicited that could either result in taboo words (taboo-eliciting trials) or neutral words (neutral-eliciting trials). In taboo-eliciting trials, there was an augmented negative wave around 600 ms after the pronunciation cue even though there were no overt errors. This component has previously been interpreted as reflecting conflict. These results indicate that taboo utterances can indeed be detected and corrected internally.