Toxicokinetics is a branch of toxicology that focuses on the study of how toxic substances enter the body, are distributed throughout the body, metabolized, and eventually eliminated. It involves studying the absorption, distribution, metabolism, and excretion of toxic substances, as well as how these processes are influenced by factors such as age, gender, genetics, and environmental conditions. Toxicokinetics is important in understanding the toxic effects of substances and predicting how they will behave in the body.