5-fluorouracil, an antimetabolite agent, has been widely used since 1957 for treatment of varied types of cancer such as gastro-intestinal, pancreas, breast, lung, head and neck malignancies. Cardiotoxicity of 5-fluorouracil is rare and was first described in 1975. It can induce severe complications and involve vital prognosis in the short-term. These complications are less known by cardiologists than medical oncologists. The following clinical case represents a potentially serious and rare case of completely reversible cardiogenic shock in a patient with a colo-rectal cancer. A better knowledge of these complications could reduce cases of death by an earlier diagnosis, and a better evaluation of patients with high cardiotoxicity risk.