Background and Objectives: The rise in suicidal attempts has led to an increase in unusual intoxication cases. The ingestion of anhydrous calcium chloride (CaCl2) causes direct injury to the gastrointestinal wall via a thermal burn. Therefore, previous reports on CaCl2 ingestion primarily considered the gastrointestinal injury. Severe CaCl2 intoxication can induce a hypercalcemic crisis, presenting with arrhythmia, acute pancreatitis, and acute kidney injury. This case report details a patient with hematemesis and hypercalcemia following the ingestion of a commercial desiccant. We aimed to report the progression of the case, with a focus on the electrocardiographic manifestations. Case Presentation: A 39-year-old female presented at a regional emergency center with blood in her vomit after the ingestion of a commercial desiccant. Bloody emesis was the initial symptom, and various electrolyte imbalances developed during admission. Electrocardiogram (ECG) changes occurred early after hospitalization and disappeared before the electrolyte levels normalized. The patient was maintained in an NPO (Nil Per Os) state throughout her hospital stay. The bloody emesis and abdominal pain resolved quite early, despite her minimal mention of symptoms, possibly due to her suspected negative psychiatric symptoms. Conclusions: In this case, we observed dynamic and prolonged multiple electrolyte imbalances along with the early-phase ECG changes, all of which responded well to supportive care. This report adds to the understanding of the diverse manifestations and management of CaCl2 intoxication.