Oral cancer, also known as mouth cancer, is cancer of the lining of the lips, mouth, or upper throat. In the mouth, it most commonly starts as a painless white patch, that thickens, develops red patches, an ulcer, and continues to grow. When on the lips, it commonly looks like a persistent crusting ulcer that does not heal, and slowly grows. Other symptoms may include difficult or painful swallowing, new lumps or bumps in the neck, a swelling in the mouth, or a feeling of numbness in the mouth or lips. Risk factors include tobacco and alcohol use. With both tobacco and drinking alcohol, the risk of oral cancer is 15 times greater. Other risk factors include HPV infection, chewing paan, and sun exposure on the lower lip. Oral cancer is a subgroup of head and neck cancers. Diagnosis is made by biopsy of the concerning area, followed by investigation with CT scan, MRI, PET scan, and examination to determine if it has spread to distant parts of the body. Oral cancer can be prevented by avoiding tobacco products, limiting alcohol use, sun protection on the lower lip, HPV vaccination, and avoidance of paan. Treatments used for oral cancer can include a combination of surgery (to remove the tumor and regional lymph nodes), radiation therapy, chemotherapy, or targeted therapy. The types of treatments will depend on the size, locations, and spread of the cancer taken into consideration with the general health of the person.