There is evidence that, in spite of the Perugia consensus, acute and delayed emesis are treated in a suboptimal way. Thus breakthrough and refractory emesis as defined in this paper may be related to inadequate therapy. Several interventions have been used in attempts to stop breakthrough emesis, including use or repeat use of setrons, corticosteroids, D2-receptor antagonists including neuroleptics, or sedatives. It has been documented that refractory emesis responds to various modifications of the original antiemetic regimen, including the addition of a D2-receptor antagonist or a switch to another setron. In conclusion, no level I or II evidence-based guidelines can be given, as few adequate studies have been performed in this area, which therefore remains poorly documented.