Bentazone is a widely used herbicide considered a moderate hazard. Fatalities associated with its use are rare, with deaths reported only after intake ≥200 mL. In some studies, its use is accompanied by generalized rigidity. Malignant hyperthermia is a pharmacogenetic disease that presents a hypermetabolic response to anesthetic gases or depolarizing muscle relaxants due to calcium channel dysfunction. The classic symptoms of malignant hyperthermia include hyperthermia and muscle rigidity. We report the case of a 65-year-old man who died 4 hours after presenting to the emergency department after ingesting approximately 75 mL of Basagran M60 (bentazone 33.6%, 25.2 g). This is the smallest dose (364 mg/kg) reported in a fatal case to date. Electrocardiogram changes, including QRS widening and QT prolongation, were present, and hypocalcemia was confirmed. We propose that bentazone intoxication causes patient deterioration by a mechanism similar to that of malignant hyperthermia.