Anticipatory nausea and vomiting (ANV) are learned responses to chemotherapy that develop in up to 25% of patients by the fourth treatment cycle. Post-treatment nausea and emesis must occur before development of ANV can take place. Certain patient characteristics and other responses to chemotherapy can also be used to predict their occurrence. Once they develop, ANV cannot be controlled by pharmacologic means including use of new 5-HT3 receptor antagonists. By contrast, behavioral therapies involving relaxation, most notably systematic desensitization, can be used to effectively treat ANV. Clinic personnel including oncologists and oncology nurses as well as behavioral psychologists can effectively administer systematic desensitization to chemotherapy patients.