Frequently Asked Questions

Canker sores affect millions. Medically this condition is known as Recurrent Aphthous Stomatitis (RAS) and nearly 20 percent of the population is affected. We know you may have questions regarding canker sores. Here we answer your most common ones.

Q: I was doing research into what caused my canker sores and came across the terms aphthous ulcers and Recurrent Aphthous Stomatitis. Are these related to canker sores?

A: Yes, these terms are just other names for the appearance of canker sores. A canker sore is often referred to as an aphthous ulcer or oral ulcer. Recurrent Aphthous Stomatitis is the medical term given to an outbreak of canker sores. Here, at the Relief Center we use all the terms interchangeably.

Q: What causes canker sores?

A: It is not known exactly what causes canker sores. This is an active area of research. Current theories point to canker sores being the result of a localized autoimmune disorder. It is thought that the body's own immune cells attack the cells lining the inside of the mouth.

While the immune dysfunction is thought to be the underlying mechanism of canker sore formation, it is believed that certain factors may initiate the chain of events leading to canker sore formation. These factors include sensitivity to certain foods, certain ingredients in toothpaste, stress, and trauma to the lining of the mouth. Click Here for more canker sores products

A: Canker sores and cold sores share many of the same features. Both are painful and both are often caused by stress. Although they frequently appear on the lips and edges of the mouth, cold sores can occur in the mouth as well where they may be mistaken for canker sores.

The main differences are that inside the mouth cold sores tend to occur more on the bound or non-movable parts of the mouth such as the roof of the mouth. Cold sores are caused by a virus and therefore can be passed from person to person.

Canker sores are not caused by a virus and therefore can not be passed from person to person. They do not appear outside of the mouth.

Q: Are canker sores contagious? Can I pass them on when I kiss my significant other?

A: You can not pass canker sores from person to person because they are not caused by a virus or by bacteria. Many health professionals, however, advise people with canker sores not to kiss. This is because bacteria from another person's mouth could potentially infect open canker sores.

Q: I seem to get canker sores during my menstrual period. When I was pregnant I seemed to get some relief. Was this just me or something that other women experience?

A: Actually this experience is not unique to you. Often women experience canker sores only during certain periods of their menstrual cycle. A common report is the complete absence of canker sores during pregnancy. This prompted some researchers to experiment with hormonal therapies in hopes of creating a new treatment for canker sores. Unfortunately, these trials were largely unsuccessful.

Q: Someone told me that SLS in my toothpaste may be responsible for my canker sores? What is SLS exactly?

A: SLS stands for Sodium Lauryl Sulfate and it is used as a detergent in toothpastes. Recent studies, however, have shown that SLS may be responsible for canker sores in susceptible people. It is thought that the detergent may weaken the lining of the mouth making it susceptible to canker sore formation.

Many of my patients and visitors to the website have experienced relief from canker sores after switching to SLS free toothpastes. For more information on SLS and canker sores see our SLS article.

Q: Why do canker sores hurt so much?

A: Canker sores are actual ulcerations of the skin lining the inside of the mouth. As a result the sensitive tissue underneath is exposed to the contents of the mouth.

Imagine if you were to rub the skin off of your arm and then apply salt water to the affected area. This is basically what is happening inside your mouth with your canker sores.

Q: I often get canker sores when I get sick? Are they caused by the same germs which are responsible for my colds?

A: Many people seem to suffer from canker sores during sickness and therefore associate the canker sores with the germs or viruses causing the illness.

Canker sores, however, are not caused by a virus or germ. The reason canker sores may be seen at the same time is that stress seems to be a factor in initiating canker sores. Stress also weakens the immune system making a person more likely to become sick as well.

Q: Unfortunately, I can no longer enjoy chocolate. It seems that after eating chocolate I come down with canker sores. Is there a connection?

A: Studies have shown that for some people there may be a connection between canker sores and the foods they eat. These people seem to get canker sores as a result of an allergic reaction to certain foods. Foods commonly associated with this allergic reaction include nuts, peanut butter, seafood, wheat products, chocolate, and milk.

Q: I once heard that vitamins may help me reduce the frequency and severity of canker sores. Is this true?

A: Deficiencies in certain vitamins and minerals - principally B12, iron, and folic acid - have been implicated in canker sore formation. In several British studies, a deficiency in the level of vitamins and minerals was seen in a significant number of RAS sufferers. U.S. studies, however, do not seem to find the same correlation between levels of these vitamins / minerals and canker sore occurrences.

If you do not have a deficiency or do not know whether or not you have a deficiency, I would not take these vitamins or minerals without first consulting a doctor. Vitamins and minerals taken in excess can often cause harmful toxicities.