Capecitabine (Xeloda, Roche, Monza), a fluoropyrimidine carbamate, is an orally administered drug that delivers fluorouracil (5-FU) selectively to the tumor. The drug has demonstrated activity in metastatic breast cancer, pancreatic cancer and colorectal cancer. In this case report the authors describe an unusually and reversible cardiac side effect which occurs to 39-year-old patient treated with capecitabine 2000 mg/m2/day for advanced gastric cancer. It is important to note that the safety data from clinical trials indicate that capecitabine has a toxicity profile typical of infused fluoropyrimidines. However, none of the studies described cardiac side effects.