Ondansetron in Treating Patients With Advanced Cancer and Chronic Nausea and Vomiting Not Caused by Cancer Treatment

RATIONALE: Antiemetic drugs, such as ondansetron, may help to reduce or prevent nausea and vomiting in patients with advanced cancer. PURPOSE: This randomized phase III trial is studying how well ondansetron works compared to a placebo in treating patients with advanced cancer and chronic nausea and vomiting that is not caused by cancer therapy.