Magnesium toxicity is a potentially life-threatening condition that can present with loss of deep tendon reflexes, respiratory depression, and cardiac arrest. In this poster we present two cases, where concurrent spinal anesthesia and magnesium administration likely produced additive vasodilatory and neuromuscular effects, contributing to significant hemodynamic instability. Comorbid conditions—including chronic hypertension and HELLP-related renal dysfunction—impaired compensation and clearance, increasing susceptibility to hypermagnesemia. Notably, magnesium toxicity can mimic neurologic emergencies such as epidural hematoma, particularly when presenting with lower extremity weakness. These cases highlight that magnesium therapy in peripartum patients is not benign and requires vigilant monitoring of renal function and serum magnesium levels to prevent rapid clinical deterioration.