Cancer cannot be diagnosed solely on the basis of a simple muffled voice. A muffled voice may be caused by other reasons, such as simple inflammation of the vocal cords, viral infection, vocal cord injury, benign tumors, and so on. Although compression of the recurrent laryngeal nerve by tumors or metastatic lymph nodes can cause the symptom of mute voice, one cannot rely on one symptom alone to determine the occurrence of cancer. If the patient has symptoms such as hoarseness, cough, foreign body sensation, etc., laryngoscopy can be used to diagnose in order to determine whether cancer has occurred. Other causes of mute voice: 1. Simple inflammation of vocal cords: patients with simple inflammation of vocal cords may have mute voice, it is recommended that patients go to the hospital for examination in time, and can be treated symptomatically under the guidance of doctors, and should not take medicines by themselves in order to avoid adverse reactions related to medicines. 2. Viral infections: Because viral infections cause upper respiratory tract diseases, such as viral colds, patients usually have a muffled voice and cough and other symptoms. 3. Benign cysts: The presence of benign cysts on the patient’s vocal cords, as well as polyps on the vocal cords, vocal cord nodules, laryngeal cancer and other malignant tumors, can lead to a muffled voice. It is recommended to go to the hospital for examination in time to exclude the possibility of malignant tumors, laryngoscopy can be done under the guidance of the doctor, and then according to the cause of the symptomatic treatment, so as not to delay the treatment, it is recommended that the patients with mute voice pay attention to the diet should be light in their daily life, try not to smoke and drink alcohol, and try not to eat spicy and stimulating food, so as not to aggravate the condition.