When a meal triggers tears
Tearing is not always a response to sadness, pain, or irritation. In gustatory lacrimation, also called crocodile tears, eating can make one or both eyes water. It may appear after an injury to the facial nerve—the nerve that controls many facial movements and carries signals involved in tear and saliva production.
A repair that takes the wrong route
Normally, branches of the facial nerve help route automatic signals to different glands. One pathway helps stimulate saliva when a person eats; another helps stimulate tears. If the nerve is damaged, as can happen during facial paralysis, its fibers may regrow imperfectly. Some fibers that would ordinarily carry an eating-related signal to salivary glands can reconnect along a route that reaches the tear gland instead.
Once those connections are in place, the brain’s ordinary cue to produce saliva—such as tasting or chewing food—can also set off tear production. The person may have no emotional reaction at all; the eyes are responding to a misdirected nerve signal.
A visible clue to nerve recovery
The tearing can emerge as facial-nerve function returns, because regrowth is when the mistaken connections form. It is a reminder that nerves do not always reconnect with perfect precision: a familiar signal can reach a neighboring destination, turning the simple act of eating into an unexpected trigger for tears.
