In an attempt to explain the self-report of smokers that cigarette smoking is relaxing, shock endurance was used to measure the amount of anxiety experienced in a stressful situation by nonsmokers, smokers who were allowed to smoke cigarettes containing either low levels or moderately high levels of nicotine, and smokers who were not allowed to smoke a cigarette. Smokers who were deprived of cigarettes and those who smoked cigarettes containing low levels of nicotine behaved more anxiously than nonsmokers and than smokers who smoked cigarettes containing moderately high levels of nicotine, but the high-nicotine smokers behaved no less anxiously than nonsmokers. These results supported the hypothesis that the calming effect attributed to smoking a cigarette is due to the action of nicotine in ending withdrawal symptoms in addicted smokers rather than to a sedative property of cigarette smoking.