After half a month of quitting, regular smokers may experience dizziness, headache, nausea, restlessness, poor sleep, apprehension, coughing, etc. This is known as nicotine withdrawal syndrome. Many smokers will give up their efforts because of the withdrawal syndrome, which can lead to relapse, and need to shift their attention and face it positively. Smoking is harmful to health, and promoting anti-smoking knowledge and the benefits of quitting should become a common phenomenon.