This chapter introduces neurotoxicology, which includes an impressive range of toxins that target the nervous system. Neurotoxins may reach the nervous system by ingestion through the gastrointestinal tract, inhalation, transdermal absorption, intravenous administration, or via external radiation. The most important procedure for determining the presence of neurotoxic disease is the clinical history. Key elements of the history include the nature of the symptoms, documentation of the exposure and any quantitative data that may be available, the proximity of the exposure to neurotoxic clinical features, the response to toxin removal, the presence of coexisting medical, neurologic, or psychiatric disorders, the family history, and the occupational status of the patient. The treatment of neurotoxic disorders revolves around prevention, removal of the toxin, specific treatment when available, and symptomatic therapy. The most relevant area of neurotoxicology for Behavioral Neurology & Neuropsychiatry (BN&NP) subspecialists is neurobehavioral toxicology.