The gag reflex is an innate reflex to protect the upper respiratory and digestive tracts from any event that could cause their obstruction. However, in some patients, this reflex may be unpredictable and exaggerated. the realization of prosthetic care can then become painful for the patient, and delicate for the practitioner. The gag reflex not only interferes with the quality of the therapeutic act but can also prevent the patient from wearing a dental appliance in which he or she had placed hopes. A perfect understanding of the different etiological mechanisms is an essential prerequisite. Indeed, depending on the etiology and importance of this reflex, the practitioner will preferentially use one therapy over another or will have to combine several treatments for the most intractable nausea.