PURPOSE: Despite the widespread use of antiemetics, nausea continues to be reported by over 70% of patients receiving chemotherapy. METHODS: In this double blind, multicenter trial, we randomly assigned 744 cancer patients to four arms: 1) placebo, 2) 0.5 g ginger, 3) 1.0 g ginger, or 4) 1.5 g ginger. Nausea occurrence and severity were assessed at a baseline cycle and the two following cycles during which patients were taking their assigned study medication. All patients received a 5-HT(3) receptor antagonist antiemetic on Day 1 of all cycles. Patients took three capsules of ginger (250 mg) or placebo twice daily for 6 days starting 3 days before the first day of chemotherapy. Patients reported the severity of nausea on a 7-point rating scale ("1" = "Not at all Nauseated" and "7" = "Extremely Nauseated") for Days 1-4 of each cycle. The primary outcomes were to determine the dose and efficacy of ginger at reducing the severity of chemotherapy-induced nausea on Day 1 of chemotherapy. RESULTS: A total of 576 patients were included in final analysis (91% female, mean age = 53). Mixed model analyses demonstrated that all doses of ginger significantly reduced acute nausea severity compared to placebo on Day 1 of chemotherapy (p = 0.003). The largest reduction in nausea intensity occurred with 0.5 g and 1.0 g of ginger (p = 0.017 and p = 0.036, respectively). Anticipatory nausea was a key factor in acute chemotherapy-induced nausea (p < 0.0001). CONCLUSIONS: ginger supplementation at a daily dose of 0.5 g-1.0 g significantly aids in reduction of the severity of acute chemotherapy-induced nausea in adult cancer patients.