A Chinese man was recently diagnosed with “crocodile tear syndrome”, a rare medical condition that causes people to shed tears whenever they eat.

Crying is usually triggered by a strong emotional reaction, such as sadness, pain or uncontrollable laughter, but in rare cases it can be activated by something as benign as eating. Last year, an elderly man, referred to only as ‘Mr. Zhang’ by Chinese media, reportedly started shedding tears when he ate. He didn’t think much of it at first, but the crying got noticeably worse when he needed to chew for longer, and this interfered with his social life. Zhang started avoiding eating in public, for fear of tears rolling down his face in front of people, so he became isolated. Luckily, he realized that this wasn’t something he could hide forever, and decided to see a doctor.

The process of recovering from facial paralysis had affected the activity of the lacrimal glands, particularly the one in his left eye. During the recovery period, the facial nerve fibers become misdirected, and the salivary nerve ends up innervating the lacrimal gland instead of the submandibular gland.

The result of this facial nerve misdirection is that stimuli such as the smell or taste of food, instead of causing salivation, excites the lacrimal gland to produce tears.

The symptoms of crocodile tear syndrome vary from patient to patient, and more mild cases are generally managed by counseling and regular monitoring. In more severe cases, the most popular treatment is botulinum toxin injections into the lacrimal gland, to stop transmission along aberrantly regenerated nerve fibers to the affected gland. The effects of the toxin last about 6 months.

Surgical interventions are also a solution, and that was the option of choice in Mr. Zhang’s case. His condition improved greatly, but sources do not clarify if the relief is permanent.