Nicotine causes the addiction to tobacco products, but it does not have serious effects on the body. The other chemicals and substances involved in smoking, however, do affect the body. Nicotine addiction causes changes in the brain that lead to further addiction and the desire to smoke. Long-term smoking has many negative effects on the body including damage to the lungs and the heart. Cigarette smoking leads to increase risk of cancer to almost every organ. Smoking also causes complication in pregnancy for both mother and child.