Dry heaving at the smell of nausea is a normal physiological reflex that many people have. The smell of nausea will cause an uncomfortable reaction, and the irritating signal will act on the central nervous system, and through the integration of the central nervous system for sympathetic and parasympathetic nerves have a certain effect and stimulating effect, which will easily lead to the receptors of the patient’s internal organs to be affected by the smell of nausea to produce a dry heaving reaction. If the patient has some digestive tract diseases, such as chronic gastritis, gastrointestinal peristalsis and other conditions, the stimulation of taste or smell is more likely to produce the dry heaving reaction, and there is also a certain relationship with individual differences.