Pharmacotoxicology entails the study of the consequences of toxic exposure to pharmaceutical drugs and agents in the health care field. The field of pharma co toxicology also involves the treatment and prevention of pharmaceutically induced side effects. Biotransformation is the chemical modification made by an organism on a chemical compound. If this modification ends in mineral compounds like CO2, NH4+, or H2O, the biotransformation is called mineralisation. Biotransformation means chemical alteration of chemicals such as nutrients, amino acids, toxins, and drugs in the body. It is also needed to render nonpolar compounds polar so that they are not reabsorbed in renal tubules and are excreted. Biotransformation of xenobiotics can dominate toxicokinetics and the metabolites may reach higher concentrations in organisms than their parent compounds. On-target toxicity is also referred to as mechanism-based toxicity. This type of adverse effect that results from pharmaceutical drug exposure is commonly due to interactions of the drug with its intended target. Adverse effects at targets other than those desired for pharmaceutical treatments often occur with drugs that are nonspecific. If a drug can bind to unexpected proteins, receptors, or enzymes that can alter different pathways other than those desired for treatment, severe downstream effects can develop. Bio activation is a crucial step in the activity of certain pharmaceuticals. Often times, the parent form of the drug are not the active form and it needs to be metabolized in order to produce its therapeutic effects. In other cases, bio activation is not necessarily needed for drugs to be active and can instead produce reactive intermediates that initiate stronger adverse effects than the original form of the drug.