Mero syndrome is a syndrome with lip and facial swelling, unilateral and bilateral peripheral facial palsy and hooked tongue as the main manifestations. The etiology is unknown and may be related to genetics, nonspecific infections, immune reactions, and other factors. The pathological changes of Mero syndrome are divided into granulomatous and non-granulomatous types, and its treatment lacks etiologic treatment methods mostly use hormonal therapy, and antihistamines, non-steroidal anti-inflammatory drugs, and antibacterial drugs can also be applied. The prognosis is relatively poor, and recurrence or transformation to chronicity often occurs. A few patients with Metro syndrome may have a combination of facial sensory abnormalities, trigeminal neuralgia, oculomotor paralysis, migraine headaches and other symptoms, and increased cerebrospinal fluid protein by lumbar puncture.