Mouth cancer is one of the most common forms of cancer affecting millions of people in the world. Its symptoms may or may not appear initially unless they become life-threatening. Some of the most common symptoms of mouth cancer include red or white patches on gum or tongue, mouth ulcer, swelling, pain or difficulty in swallowing, a persistent pain in the neck, a hoarse voice, unexplained weight loss, unusual changes in the sense of taste, pain in the ear, swollen glands in the neck, etc. The risk factors that cause mouth cancer include smoking, alcohol consumption, consumption of betel nuts, poor oral hygiene, family history, weekened immune system, sun exposure etc.