The corners of the mouth are always twitching may be related to emotional tension, facial muscle spasm, epilepsy and so on. 1. Emotional tension: excessive emotional tension, excitement, etc. can appear in the mouth twitching symptoms, can also be accompanied by panic, hand tremor and other symptoms of nervous excitement, generally relax the mood after the symptoms of symptoms can be improved. 2. Facial muscle spasm: early onset of intermittent twitching of the orbicularis oculi muscle, and then gradually and slowly spread to the side of the face of the other facial muscles, to the most obvious twitching of the muscles of the corners of the mouth, and in severe cases, can be involved in the same side of the cervical vastus lateralis muscle. 3. Epilepsy: Partial motor epilepsy seizures can be manifested as convulsions of the corners of the mouth, and if not clearly diagnosed and treated, seizures can be repeated, and can also progress to other types of epilepsy. For people with constant twitching of the corners of the mouth, except for emotional factors, it is recommended to consult a doctor as soon as possible to determine the cause of the disease and treat it.