Bioactivity guided isolation of the bark of Careya arborea afforded piperine--an alkaloid chemically known as 1-[5-(1,3-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]piperidine, which was found to possess significant central and peripheral analgesic activity. At oral doses of 10, 20 and 30 mg/kg body