Drug toxicology is a branch of biology, chemistry, and medicine (more specifically pharmacology) concerned with the study of the adverse effects of chemicals on living organisms. It also studies the harmful effects of chemical, biological and physical agents in biological systems that establish the extent of damage in living organisms. The relationship between dose and its effects on the exposed organism is of high significance in toxicology. Factors that influence chemical toxicity include the dosage (and whether it is acute or chronic); the route of exposure, the species, age, sex and environment. The goal of toxicity assessment is to identify adverse effects of a substance. Adverse effects depend on two main factors: i) routes of exposure (oral, inhalation, or dermal) and ii) dose (duration and concentration of exposure). To explore dose, substances are tested in both acute and chronic models. Generally, different sets of experiments are conducted to determine whether a substance causes cancer and to examine other forms of toxicity.

In the present book, ten typical literatures about drug toxicology published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on medical science, physiology, pharmacology, chemistry, ect. We hope this book can demonstrate advances in drug toxicology as well as give references to the researchers, students and other related people.