Nicotine is a CNS stimulant derived from tobacco plants that has both stimulating and relaxing effects on the body. It is highly addictive, causing both physical and psychological dependence, and tolerance develops with continued use requiring higher doses. Withdrawal from nicotine causes intense cravings and symptoms like headaches, nausea, anxiety, and depression. Treatment options for nicotine withdrawal include nicotine replacement therapies as well as non-nicotine prescription medications and e-cigarettes.