Two cases of 5-fluorouracil cardiotoxicity, resulting in one patient in myocardial infarction, are described. A review of the literature confirms that cardiotoxicity is a rare but genuine complication of 5-fluorouracil treatment; the cardiotoxic effect seems to range from mild angina without persistent electrocardiographic changes to severe myocardial infarction. No factors predictive of this complication were identified. The authors therefore feel it is advisable to stop 5-fluorouracil treatment when precordial pain occurs, even if the ECG (after angina) is normal, since angina can in some cases result in myocardial infarction.