Cancer cachexia is characterized by progressive, involuntary weight loss in patients with cancer. Cachexia is a common cause of death in patients with cancer in the advanced stage. It is well known that cancer patients with significant weight loss are subject to a high risk of postoperative complications. Intravenous hyperalimentation (IVH) has been applied to anticancer treatment when patients are unable to take sufficient nutrients orally. It is mandatory to take efficacy of antineoplastic therapies into account in attempting to assess response to nutritional repletion in cancer patients. Nutritional support is effective in maintaining body weight of malnourished cancer patients, although it is difficult to maintain body cell mass expressed as intracellular water. In other words, there is a discrepancy between changes in body composition and weight loss in undernourished patients with cancer. It seems that intravenous hyperalimentation has no documented benefit to cancer patients undergoing antineoplastic treatment from the standpoint of improved patient survival in the prospective, randomized trials of nutritional support. Therefore, further studies are needed in order to improve tumor-bearing host survival by means of nutritional management, i.e., glutamine enriched solution, amino acid imbalance solution, and anticachectic drugs on the basis of the deranged metabolism in cancer.