Severe epileptic encephalopathy and fulminant liver failure with cerebral edema in two infants given tea brewed from home-grown mint plant leaves are reported from the Departments of Pediatrics and Neurology, University of California, Davis Medical Ceneter, Sacramento. The 1st case, an 8-week-old Hispanic boy failed to awaken the morning after developing fever and mild respiratory symptoms on the day before admission. His eyes were rolled back and he was hypotonic and hypoglycemic. He had hepatomegaly, gastrointestinal bleeding, and multiple organ failure. Generalized seizures developed on the 2nd day, and he died on the 4th day after admission. Tea brewed from a mint plant had been given by the mother for colic and congestion. Autopsy findings revealed hepatocellular necrosis, hemorrhagic renal necrosis, adrenal hemorrhage, cerebral edema, and necrosis and vacuolation of midbrain. The 2nd case, a 6-month-old Hispanic boy had a generalized tonic-clonic seizure following a 1 day illness with fever and vomiting. On admission, his serum glucose was 7 mg/dL. pupils were dilated and minimally reactive, and he had a coagulopathy and metabolic acidosis, gastrointestinal bleeding, and petechiae over the lower limbs. The liver was enlarged and liver function tests markedly abnormal. CT showed a straight sinus hemorrhage. Generalized seizures recurred on the 7th day, the EEG showed persistent epileptiform activity, and he developed a spastic rigidity. At discharge 2 months later, liver enzymes remained elevated, and a muscle biopsy showed myopathic changes. Tests for an infectious cause were negative. Serum collected at admission contained 25 ng/ml of pulegone and 41 ng/ml menthofuran. [1]

COMMENT. Most mint teas are nontoxic, but some home-grown mint plants used to brew home-made teas may contain pennyroyal oil, a highly neurotoxic and hepatotoxic agent. When mistakenly given to infants as a remedy for colic and other minor ailments, the chemical metabolites of the oil, pulegone and menthofuran, can deplete tissue enzymes and lead to multiorgan failure. The liver and brain are particularly vulnerable, and symptoms of mint tea poisoning include coma and convulsions. Other manifestations are cerebral edema, metabolic acidosis, hypoglycemia, gastrointestinal bleeding, and intravascular coagulopathy. Treatment consists of gastric lavage, activated charcoal, and N-acetylcysteine to replace hepatic glutathione depleted by the toxin. Hispanic parents especially, who frequently treat infants with home-grown herbs, should be warned of the hazards of certain mint plants. This report alerts physicians to the potential toxicity of mint teas and the inclusion of herbal remedies in the differential diagnosis of infantile epileptic encephalopathy.