In this video, Mark Yoder (N.P., Oncology) gives an introduction to nausea, and some tips for dealing with this common treatment side effect. Nausea, or experiencing a strong urge to vomit, is an unpleasant reality for most individuals with cancer. Science believes that vomiting is controlled by the nausea center of the brain. It is not known, however, why one person gets extremely nauseous, while another does not even have a trace of upset stomach when exposed to the same chemo, radiation, hormones or pain medications. Sometimes, the tumor may be directly or indirectly affecting the digestive system, leading to nausea. In many individuals, the mind and emotions can cause an upset stomach. All those factors can and do trigger the nausea center of the brain.