Before a new drug is introduced in therapeutics it is necessary to determine its pharmacodynamics,Kinetics and how best it can serve human beings and domestic animals.Obviously,because of their inherent toxicity,such exploratory studies cannot be undertaken in human beings.The nearest equivalent to the complex human organism is to be found among mammals such as monkeys,dogs,cats,rabbits,guinea pigs,rats and mice.It is with these species that pharmacologists work while attempting to check and chart the pattern of a drug s action and achieve thereby some advance estimate of its clinical value,limitations and possible dangers.The data are used to predict starting and maximal doses in human studies and when evaluated in conjunction with the data obtained in human pharmacokinetic studies serve as an index for animal to human comparison and extrapolation.The influence of Piper longam on the metabolism of diclofenac in albino rats has shown that the half life of dielofenac as well as the efficiency is enhanced than when giving the drug alone.This is because of the microsomal enzyme inhibition by Piper longum.