Toxicology is the study of the interaction of chemicals with the living system. Like the name suggests, it involves the study of symptoms, mechanisms and treatments of individuals who have been exposed to toxic and poisonous substances. This branch of study of effect of toxins and their subsequent treatment originated amongst early cave men that discovered poisonous plants and animals and used the poison in hunting or in warfare. However, it was only in the twentieth century that an independent science of toxicology emerged. It has various branches like environmental toxicology, flood toxicology and clinical toxicology.

Toxicology puts a value on the risk involved when certain chemicals react with the body systems and thus curbs the potential chemical threats that can be found in everyday living. It is a combination of different fields of sciences like chemistry, biology and statistics that together bring about an understanding of the potency of a chemical. Thus the scientist, after carrying out exhaustive research on these areas of concern, finally comes to the conclusion of finding out factors that determine the outcome of an exposure to certain chemicals under certain circumstances.

Toxicology involves the progressive study of measurements of biochemical and functional changes in the immune system, endocrine system and the neurological system. In toxicological studies, the researcher studies the threshold of the body that can endure a certain amount of chemical before the chemical turns out to be toxic or harmful to the body. This is referred to as dosage levels. The dosage level is determined by the chemical structure, the chemistry and the biochemistry of the chemical in question. Along with getting to know the mode of action and toxicity brought about a certain chemical substance the researcher also needs to know the biological processes and cellular processes in the body that the chemical tends to affect.

Chemical concentration plays an important role in when designing toxicity studies. This may include individual chemicals or mixtures of the same. This study has been applied widely onto forensic studies. It is used in the measurement of alcohol, drugs and other poisonous substances in specimens of biological origin. Interpreting such findings can prove to be important turning points in criminal investigations. It has proved to be one of the major applications of toxicology due to increase in crime rates and other related deaths. There are numerous areas of specialty when it comes to forensic toxicology but the most sought field is postmortem toxicology.

A toxicology test utilizes blood or urine samples to detect the presence of drugs. In certain cases substances like stomach contents, sweat or saliva may also be checked. Generally, laboratory methods are better able to detect drugs in urine than in blood. The reliability of toxicology tests depends on the methods used by the laboratory.