Background: Nutritional support containing fat emulsion, amino acids, and glucose is widely applied to improve the metabolic status of tumor patients, however, the related adverse reactions have been rarelyreported. Here, we reported two patients with tumor who received parenteral nutrition (PN) with injections of fat emulsion (10%)/amino acids (15)/glucose (20%) experienced severe side effects, and subsequently provide guidance information for the clinical administration of fat emulsion (10%)/amino acids (15)/glucose (20%) injection.Case Description: The first case was a 69-year-old female, diagnosed with cholangiocarcinoma T2N1MX IIIB by magnetic resonance imaging (MRI). This patient received 1,000 mL fat emulsion (10%)/amino acids (15)/glucose (20%) intravenous injection once a day. After receiving PN solution, she suddenly experienced chills and aversion to cold, auscultation detected the presence of rough respiration in both lungs, with some dry rales. The blood pressure was 175/100 mmHg. The second case was a 69-year-old male, diagnosed with lung cancer (differentiated squamous cell carcinoma in the lower lobe of the right lung, stage T4NxM1 IV), and secondary hepatic malignant tumor. He received 1,000 mL fat emulsion (10%)/amino acids (15)/glucose (20%) injection once a day. Then he presented the aggravation of chest pain and breath obstruction, chills, cyanosis, and wheezing. Breath sounds were rough in both lungs, with a small amount of wheezing. In both cases, their symptoms were relieved after immediately stopping the injection, and they did not experience similar side effects when they received the injection again a few days later. We considered that these patients had experienced a serious adverse reaction caused by fat emulsion (10%)/amino acids (15)/glucose (20%) injection after excluding the issues of fat overload syndrome, infusion speed, and quality of the medicine.Conclusions: Fat emulsion (10%)/amino acids (15)/glucose (20%) injection is suitable for patients with gastrointestinal insufficiency requiring PN support to improve their metabolic status, especially for those with advanced tumors. However, physicians should carefully inquire about the patient's allergy history, and formulate an individualized PN administration plan. Appropriate management of infusion speed and formula is necessary to ensure the safety of medicine application.