Intravenously administered cytotoxic drugs and biological antibodies may cause infusion reactions, the majority of which are mild. Severe, even fatal reactions occur as well. Adrenaline is invariably the most important treatment of a severe reaction. When contemplating whether the patient should again be subjected to a drug having caused a reaction, aspects to be considered include the degree of severity of the reaction, pathogenetic mechanism, the patient's general condition and cancer stage as well as the possibility to change the anticancer drug that caused reaction to another drug having a similar action on the patient's disease.