The most difficult time to quit smoking is about 1 week after quitting, but it still depends on the smokers’ respective different physiological and psychological reactions. The withdrawal reaction occurs after quitting smoking. Clinical studies have shown that smokers can experience physiological discomfort within 24 hours of quitting, such as strong cravings to smoke, irritability, anxiety, lack of concentration, weakness in the limbs, and a range of other manifestations. The duration of these reactions and the intensity of the reactions produced vary from person to person, and most smokers experience a gradual disappearance of these symptoms within 3 weeks. Physiologically speaking, the body’s adaptation and discomfort to the sudden drop in nicotine levels from previous smoking levels will be strongest in the first week, and then the physiological withdrawal response will diminish over time, eventually disappearing about 3 weeks after quitting. In addition, there are many ways to relieve discomfort during smoking cessation, such as alternative therapies, chewing gum, or engaging in other exercise programs to distract from the desire to smoke. For smokers who have developed severe tobacco dependence, they can seek professional medical help at a hospital’s smoking cessation clinic and choose smoking cessation medications or methods to quit smoking under the guidance of a physician to achieve the goal of quitting.