The metabolism of some food additives related to piperonal in the rabbit.

1. The metabolism of piperonylidene acetone, and the food additives piperonyl acetone, piperonyl acetate and piperonyl isobutyrate were studied in male rabbits after oral doses of 100 mg/kg. 2. Both piperonylidene acetone and piperonyl acetone were extensively excreted as 4-(3,4-methylenedioxyphenyl)-butan-2-ol to the extent of 71.5% and 81.5% dose respectively in the three-day urine. 3. The esters, piperonyl acetate and piperonyl isobutyrate, were both metabolized to piperonylic acid, to the extent of 70.5% and 11.4% of dose respectively, in the three-day urine.