A muffled voice from a cold may be caused by a viral infection of the throat, vocal cords causing a localized inflammatory response, and other causes. Colds are acute upper respiratory tract infections caused by viral infections. Viral infection of the throat will cause inflammation of the mucous membrane of the throat, resulting in localized congestion and edema, causing swelling and pain in the throat. If the viral infection invades the vocal cords, it will cause edema and congestion of the vocal cords, thus affecting the frequency of vocal cord vibration, and there is a mute voice. Also during a cold the patient will have a violent cough, which can aggravate the damage to the throat and may worsen the symptoms of a muffled voice. Mute voice can also be caused by other diseases, if the symptoms do not improve or aggravate, it is recommended to go to the regular hospital for examination, to clarify the cause and timely treatment.