Pharmacokinetics is a division of pharmacology dedicated to the purpose of the fate of substances administered externally to a breathing organism. In practice, this regulation is applied mainly to drug substances, though in standard it concerns itself with all way of compounds ingested or otherwise delivered superficially to an organism, such as nutrients, metabolites, hormones, toxins, etc. Pharmacokinetics is often divided into numerous areas including, but not limited to, the level and rate of Absorption, Distribution, Metabolism and Excretion. This sometimes is referred to as the ADME system.

Absorption is a core entering the body. Distribution is the dispersion or diffusion of substances throughout the fluids and tissues of the body. Metabolism is the conversion of the substances and its daughter metabolites. Excretion is the abolition of the substances from the body. In unusual cases, some drugs irreversibly accumulate in a hankie in the body.

Pharmacokinetics is often studied in concurrence with pharmacodynamics. So while pharmacodynamics explores what a drug does to the body, pharmacokinetics explores what the body does to the medicine.