Nausea and vomiting are well known and the most distressing side-effects of a high dose chemotherapy regimen. The administration of selective 5-HT3-receptor antagonists (5-HT3 RAs) in combination with a corticosteroid (= antiemetic standard therapy) is effective for the prevention of those adverse effects in 70 to 80 % of patients. However, 25 to 40 % of the patients still suffer from vomiting and nausea in the delayed phase of the chemotherapy. Superior protection could be achieved with the addition of Aprepitant (EMEND®) to the antiemetic standard therapy in acute and delayed phases of highly emetogenic chemotherapies. The enhanced antiemetic protection can be maintained over multiple chemotherapy-cycles to an extent superior to that of standard therapy alone (de Wit et al., 2003).