Toxicity studies with ethyl maltol

Ethyl maltol, a new flavor-enhancing agent, was evaluated for biological safety by acute, subacute, and chronic administration and compared with its homolog, maltol, a naturally occurring food constituent. In single-dose, oral studies ethyl maltol was slightly more toxic to laboratory animals than maltol; however, in subacute, 90-day studies this situation was reversed. In rats, maltol at 1000 mg/kg/day inhibited normal growth and produced kidney damage. Ethyl maltol at the same dose caused no gross effects, but the same type of kidney lesions at a lower incidence was observed microscopically. Maltol caused debilitation and death in dogs at 500 mg/kg/day, with accompanying signs of acute hemolysis and altered hepatorenal function. Ethyl maltol at the same dose produced transitory signs of a mild hemolytic anemia. This chemical was well tolerated for two years by rats and dogs. No adverse toxic, reproductive or embryogenic effects at doses up to and including 200 mg/kg/day were observed. Thus, ethyl maltol appears to have a wide margin of safety and, by repeated administration, is less toxic than its homolog maltol.