Although rare, intravenous injection of foreign substances during childhood can cause fatal complications. Most of the cases reported in the literature are accidental intravenous administrations of enteral feeding formulas. To the best of our knowledge, this is the first case of intravenous injection of cow's milk. In this report, we discuss the clinical presentation and treatment of a 17-year-old nursing student who injected pasteurized homogenized cow's milk into herself due to curiosity. The girl presented to our emergency department after this injection. During admission, she presented with angioedema, gastrointestinal symptoms, dyspnea, and tachycardia associated with resistant hypotension. She, then, developed leukocytosis and elevated D-dimer levels, as determined in the laboratory. The patient was diagnosed as having anaphylaxis with clinical presentation and cow's milkspecific IgE positivity, based on laboratory findings. The patient was initially treated with adrenaline, corticosteroids, and antihistamines. Inotropes including catecholamines and wide-spectrum antibiotics were added into the therapy for resistant hypotension and sepsis prophylaxis. Low-molecularweight heparin treatment was given for the elevated D-dimer levels and prevention of embolic events. With these therapeutic interventions, there were no signs of sepsis, thrombosis, embolus, and multi-organ failure. The patient was discharged without any neurological complications or sequelae on the 6th day of hospital admission. Although sepsis and septic shock development is usually expected after the injection of foreign substances such as in this case, interestingly, there was an anaphylactic reaction caused by the patient's subclinical cow's milk allergy.