People with chronic medical conditions such as asthma, diabetes, cardiovascular disease, cancer and HIV/AIDS are particularly susceptible to the adverse effects of tobacco. Smokers with HIV infection who quit are more likely to respond well to HIV treatment and are less likely to die than HIV-infected smokers who continue to smoke. Benefits of smoking cessation after cancer diagnosis include decreased risk for treatment complications, decreased risk for second primary tumors, improved survival rates, and improved quality of life. Even smokeless tobacco (chewing tobacco) contributes to cancers of the mouth and throat, periodontal disease and tooth decay, and pregnancy-related problems. Never starting to use tobacco is a better strategy than having to stop. About 70% of the 44.5 million adult smokers in the United States want to quit, however, of those who try to quit in a given year, fewer than 5% succeed. On average, former smokers report 10.8 attempts to quit over a period of 18.6 years before successfully quitting for good. Effective treatments can double or triple quit rates but, unfortunately, many tobacco users never try them. Smokers who utilize behavioral and/or pharmacologic interventions can experience success rates of approximately 20% at least 6 months after quitting. Nicotine replacement therapies came on the market in 1984 with the introduction of nicotine gum. These therapies reduce the physical withdrawal symptoms allowing the smoker to focus on dealing with the behavioral and psychological aspects of quitting.