Patients receiving parenteral nutrition (PN) usually have conditions that require intravenous (IV) medications. Antibiotics, and cardiovascular, gastrointestinal and electrolyte agents are commonly prescribed for these patients. When the gastrointestinal tract is compromised, parenteral administration of these agents is often necessary. Because of the complex nature of PN and IV medications, a potential exists for serious or life-threatening drug and nutrient interactions to occur if procedures are not in place to foster their safe administration. This article will describe the physico-chemical characteristics of PN and concepts used in dealing with issues of drug and nutrient interactions that occur in patients requiring PN.