This was a prospective, phase II, randomized pilot study. Patients were randomized 5 days before the start of Ox to receive either vitamin E at 400 mg daily or placebo, until after the end of the Ox-based chemotherapy regimen. The investigators evaluated PN intensity using the CTCAE version 3 and specific Ox PN gradation scales. The investigators included patients with colorectal and gastric cancers scheduled to receive Ox-based chemotherapy. Both groups received calcium and magnesium supplements before and after oxaliplatin infusions.