Dry heaving can be caused by both physiological and disease-related factors. Physiological factors are mostly seen in conditioned reflexes, early pregnancy reaction, etc., disease factors are considered gastrointestinal diseases, pharyngitis, etc.. 1. Physiological factors: (1) Conditioned reflex: After smelling unpleasant odors, it will lead to conditioned reflexes in the airway, which will also be manifested as nausea and vomiting, so it is a relatively normal physiological conditioning that does not require special treatment. (2) Early pregnancy reaction: women will be pregnant due to hormone level disorders, epigastric discomfort, regurgitation phenomenon, especially after smelling the odor, the symptoms are obviously aggravated. 2. Disease factors: (1) gastrointestinal diseases: such as chronic gastritis, peptic ulcer, gastric mucous membrane damage, when smelling the odor, stimulated, manifested as epigastric discomfort, regurgitation, nausea, vomiting; (2) pharyngitis: during the onset of the patient’s vomiting center nerve is also more sensitive to odor. When you smell the odor, you will involuntarily hold your breath, which will lead to nausea due to the stimulation of the throat area. Smell the odor of dry vomiting patients in the exclusion of physiological factors, need to pay attention to timely medical treatment, under the guidance of the doctor.