3 Tips to Get Rid of Canker Sores FAST Dr. Janine has three helpful pieces of advice when it comes to quickly getting rid of canker sores. She suggests avoiding toothpastes with SLS (sodium lauryl sulfate), as this may worsen the condition. Additionally, apple cider vinegar applied directly to your canker sore via a Q-tip could provide relief in no time. Lastly, Dr. Janine points out that canker sores may be a sign of a vitamin B12 deficiency, so taking a natural whole-food cobamamide supplement