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Gag Reflex Causes

Gag Reflex Causes

This article provides some information about gag reflex, the mechanism behind it, its abnormalities and causes, and the cure for the same, that might prove beneficial.
Ishani Chatterjee Shukla
Last Updated: Apr 22, 2018
Gag reflex is a normal reflex that is characterized by a feeling of throwing up. This feeling is activated whenever an object in the mouth touches the back of the tongue, the roof of the mouth, the area around the tonsils, or the back of the throat (and touches the soft palate). The irritation caused to the pharynx by such an activity always, without fail, evokes a disgusting feeling as if one is going to throw up. There are different levels of sensitivity among different people with regards to the causes and extent of gag reflex. Gagging is a natural phenomenon which is meant to prevent anything, which is not part of the natural eating and swallowing process, from entering the throat in order to keep the person from choking by obstruction of the respiratory tract, the upper part of which is connected to the upper part of the digestive tract. However, sometimes gagging is artificially induced by sticking one's finger inside the mouth, far down the throat, to orally expel food that was recently eaten. This method is widely used by bulimics, victims of a kind of eating disorder, who frequently induce vomiting this way soon after eating something.


Whenever something that is not part of the natural swallowing process enters the throat so far as to touch the soft palate, the back of the throat contracts and one gets a feeling that he/she is about to vomit. The glossopharyngeal nerve fibers, which pass from behind the nasal cavity, pick up the sensation whenever an unnaturally large amount of food is swallowed or something other than food is attempted to be pushed down the throat. These nerve fibers transmit the gag sensations to the solitary tract and spinal trigeminal nuclei. Finally, these signals reach the brain which sends back instructions, in the form of electric pulses and chemical signals, back to the pharyngeal nerves to contract and cause such invasive objects to be expelled. Moreover, it takes even less than a second for the gag reflex to take place as a result of the to-and-fro transmission of biological information between the pharynx and the brain.

Abnormalities and Causes

In broad terms, there are two conditions that are considered as abnormal gag reflex issues. One is an absence and another is a hyperactivity of gag reflexes. An absence of gag reflex is marked with the subject feeling no impulse to throw up even when an object goes past the soft palate. The reason behind this is the absence of pharyngeal sensation due to defects in the nerves or neural signal transmission mechanism. Most common absent gag reflex causes are damaged glossopharyngeal or vagus nerves, brain death, or any other damage to the nerves or neural transmitters involved in the gag reflex induction process. Hyperactive gag reflex is characterized by high sensitivity levels in the pharyngeal nerves and surrounding area of certain individuals which leads to evocation of gag reflex at the slightest instance. This overactivity of the gag reflex is generally experienced by infants who are often not able to swallow their food properly and tend to throw up much of it. Overactive gag reflex causes in adults, though rare, may include sensitivity to certain foods, reactions to some sort of medication, indulging in activities that involve high-intensity movements such as swimming, running, etc. Hyperactive gag reflex causes often include dental treatment sessions and indulging in prolonged periods of excessive laughter.


There are many natural, as well as therapeutic and medical ways of stopping gag reflex problems. Natural cures include distracting oneself and breathing deep to avoid the gag reflex to take over as soon as he/she feels its onset. For people who have very sensitive gag reflexes and are more often than not anxious about controlling it, gag training of the throat is a good way to desensitize the pharyngeal area to a certain extent. An anti-gag reflex spray (or a numbing throat spray) may be used to numb the nerves around the pharynx that transmit neural information to the brain regarding the unnatural entry of an object beyond the precincts of the upper front throat.

Artificially inducing gag reflex on a frequent basis, as done by those affected by bulimia, may cause significant and permanent damage to the throat. This is a natural reflex designed to prevent choking due to unintended swallowing. Any abnormality in the form of absence or hyperactivity of the same, especially absent gag reflex, should be taken seriously as they may be symptomatic of other underlying disorders and disturbances.

Disclaimer: This HealthHearty article is for informative purposes only, and should not be used as a replacement for expert medical advice.