The aim is to explore how the package, PK, is used in analyzing pharmacokinetic data. In the process we find the peak concentrations ( C max) , peak time ( T max) , terminal half-life ( t 1/2) and area under the curve ( AUC).The peak time and the peak concentration are obtained directly from the observations. The terminal half-life is used to describe the decay of drug concentration in the terminal phase while area under the curve is used to measure the amount of drug absorbed or the efficiency of physiological processes that characterize the drug elimination [1]. Data is also described by interpolating or extrapolating with functions such as monoexponential, biexponential or multiexponential models .They are used to reduce data into a small set of parameters or test if the hypothesis incorporated in the function is fulfilled by the observed values. By changing the amount of the drug its properties can be observed by assessing the corresponding values of area under the concentration versus time graph and other parameters.