Parenteral iron, in the form of intramuscular injection or intravenous infusion of iron dextran, is commonly used to treat iron deficiency. Constitutional symptoms, anaphylaxis, and rarely death are risks associated with the use of iron dextran for this purpose. However, iron supplementation of TPN solutions to meet daily requirements can be accomplished safely. We propose that iron dextran added to TPN is well tolerated by patients because the amounts employed are small and the infusion times are long. To illustrate, we present a case where rapid administration of parenteral iron was associated with allergic type symptoms. Inclusion of daily requirements of iron in the TPN solution prior to and subsequent to this reaction did not elicit symptoms.