Nicotine replacement therapy (NRT) is a non-tobacco form of nicotine preparation that replaces the nicotine in tobacco with a small dose of safe nicotine, which provides less nicotine than that obtained from smoking, but enough to reduce withdrawal symptoms. After a period of use, the smoker’s nicotine intake is gradually reduced to a minimum, and the smoker is able to overcome the habit of smoking and achieve successful cessation. Nicotine replacement therapy has been used for 32 years since 1978 and has long been recognized and recommended by the World Health Organization and the U.S. Department of Health. Some departments and consumers do not consider nicotine addiction to be a disease and question the safety and effectiveness of nicotine replacement therapy, resulting in the slow development of nicotine replacement therapy and its products in China. Caution Use with caution in patients with severe cardiovascular disease (e.g., occlusive peripheral vascular disease, cerebrovascular disease, stable angina pectoris and decompensated heart failure), vasospasm, uncontrolled hypertension, moderate to severe liver disease, severe renal disease, duodenal and gastric ulcers. It should be used with caution in patients with hyperthyroidism and pheochromocytoma. Patients with diabetes may require lower insulin doses after quitting smoking.