Objective: To investigate the effect of coenzyme complex on decreasing cardiotoxicity in elderly patients with gastrointestinal cancer who were treated by chemotherapy. Methods: From September 2011 to February 2015, we recruited 54 elderly (with more than 70 years of age) patients with gastrointestinal cancer, with advanced disease. Then treated with chemotherapy combined with or without coenzyme complex. After two cycles of treatment, the effect of coenzyme complex on decreasing cardiotoxicity were evaluated. Results: Chemotherapy was combined with coenzyme complex in 32 patients (22man, 10 woman; median age: 74 years, range: 70-87 years) without coenzyme complex in 22 patients (15man, 7 woman; median age: 73 years, range: 70-80 years) with gastrointestinal cancer. Cardiac event was significantly lower in patients treated with chemotherapy combined with coenzyme complex (p<0.01). Conclusions: Coenzyme Complex decreased cardiotoxicity when combined with chemotherapy in treating elderly patients with gastrointestinal cancer.