Mouth cancer is the commonest cancer in our country. The disease can arise in one of the sev structures with in the mouth like the inside lining of cheek [commonest] tongue, gums, roof of mouth etc. It is commonly observed that a mouth cancer starts as a pearly white patch in the mouth which cannot be scraped off. Very often this is caused by chronic tobacco chewing. All such white patches [leukoplakia] will not develop into cancer, but some will certainly. So it is most essential such patches are regularly observed and treated by competent doctors. One can learn to examine the mouth using a mirror himself/herself to see clearly the inside of cheek, tongue, sides and undersurface, floor of mouth, the gums and areas joining the gums and cheek, the roof of mouth and lips. Any red discolouration or white patches or in fact any deviation from normal should be shown to the doctor for his advice. An ulcer caused by sharp teeth, repeated injuries to the tongue and cheek, an ill fitting denture producing constant irritation and injury are also found to progress into cancer if left untreated.