Nicotine has been developed as a medication to assist smoking cessation, and is being considered as a possible drug for long-term maintenance of non-smoking. It is also undergoing evaluation as a possible treatment for several medical disorders, including ulcerative colitis, Alzheimer's disease, Parkinson's disease, Tourette's syndrome, attention deficit disorder, spasticity, and sleep apnea. Understanding its safety and toxicity is essential for drug developers, drug regulators, and clinicians making risk/benefit decisions about long-term nicotine therapy. Research on nicotine toxicity is...