Laryngitis, lar uhn JY tihs, is an inflammation of the tissues of the larynx, or voice box. It may be caused by various conditions. Sometimes germs invade the tissues and cause them to become inflamed. Doctors believe that laryngitis may result from the use of irritating materials, such as tobacco and alcohol. Breathing irritating substances may also inflame the larynx. Improper use of the voice, which puts extra strain on the larynx and the vocal cords, may frequently cause laryngitis.