Canker sores are medically known as apthous ulcers, describing a sore that erupts inside of the lips, mouth, cheek, and/or gum line. They are small sores ranging from a few millimeters to a centimeter in diameter, featuring red borders and whitish or yellow centers. They are painful to the touch and are easily irritated by eating (especially spicy, rough texture, or high-temperature foods), drinking (especially carbonated soft drinks or alcohol), or while brushing. Upon forming, the soft tissue surrounding the canker sore site will swell and appear reddened. They differ from cold sores in that they develop inside of the soft tissues of the mouth and are not contagious. They are common in children and young adults. The exact reason for their development is unknown; however, canker sores are associated with stress and mechanical injury (e.g. accidental bite/chew, mouth irritation, dental appliance irritation). They also develop as a response to some food allergies, nutritional problems (e.g. vitamin deficiencies), and hormonal or autoimmune changes and fluctuations. Canker sores disappear within 7 to 10 days without treatment. Treatments are designed to relieve oral pain and to reduce further irritation or recurrent trauma to the site (e.g. biting the sore). Treatment includes: Easing pain. Use ibuprofen, acetaminophen, or aspirin to relieve pain. Use ice as a local anaesthetic over the injury site. You can also use a benzocaine gel (Anbesol) to numb the area, especially after bed. Rinse with salt water to cleanse the wound. Dissolve 1/4 to 1/2 tsp. in a few ounces of warm water and swish gently around the wound. This may sting a little, but it will help cleanse the wound of added bacteria. My favorite tip involves: After rinsing the canker sore with salt water, dab a liberal amount of milk of magnesia (Mylanta) onto a Q-tip and gently rub the solution over the sore. Be sure to repeat with the clean side of the swab. Do this after brushing your teeth in the morning and before you go to bed, before applying any additional medication or gel. The milk of magnesia is sufficient enough to cool down the injury site, and some sources indicate that chemical properties in the antacid help promote healing. Seek medical attention if: Sores are unusually large or persistent, lasting three weeks or more without signs of healing. This may indicate a more serious autoimmune response which may require prescription treatment (usually an oral mouthwash). Sores are painful and cannot be controlled through self-care measures. Or, if the canker sores accompany high fever or swollen lymph nodes. Again, these conditions might require different medical attention. For more information, click here to access a Google search on canker sores. Tips above provide by the Mayo Clinic.