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.
