Pharmacokinetics is what the body does to the drug. The knowledge of kinetics is very important for budding doctors to understand how dosage schedules are formed for various patients and diseases. Basically, the process of pharmacokinetics involves 4 steps, i.e. ADME. The knowledge about pharmacokinetic principles and their clinical significance is very important for doctors to generate dosage schedules, to monitor therapy, to modify schedules in case of diseases, etc. Clinical pharmacokinetics is the name assigned to science discipline dealing with the application of pharmacokinetics to the safe and effective therapeutic management of the individual. Bioavailability, volume of distribution, half-life, clearance, loading dose, and maintenance dose are important pharmacokinetic parameters, which are discussed in this chapter.