We prospectively studied, how certain patient characteristics modify the risk of chemotherapy induced and conditioned nausea and vomiting. Young age and previous history of nausea and vomiting were factors associated with both chemotherapy induced nausea and vomiting as well as conditioned nausea. Conditioned nausea was significantly associated with having received two-day compared to one-day mode of chemotherapy, previous distress during blood samples and odor memory. Tentative associations were also found between a history of flushing and chemotherapy induced nausea and vomiting as well as between autonomic perception, odor associations and conditioned nausea. The investigated variables explained a larger part of the variance in conditioned compared acute nausea and vomiting.