Anticipatory nausea and vomiting.

Anticipatory nausea and vomiting (ANV) is not only a learned response but can occur without prior exposure to chemotherapy depending on patient emotional distress and expectations. The best method to avoid development or reinforcement of ANV is to avoid both vomiting and nausea from the first exposure to chemotherapy. If ANV develops, benzodiazepines have been documented to help in adult patients, and several psychological techniques are also of help, including systematic desensitization. The evidence on which these conclusions are based is reviewed in this article.