Some experts recommend the use of toothpaste to get rid of cold sores. Toothpaste is believed to slow circulation around the sore and dry it out. However, some toothpaste ingredients may actually agitate a cold sore, explains TheraBreath.
U.K. allergy blog What Allergy? recommends applying toothpaste to a cold sore as an effective home remedy. Dr. Andrew Weil, known for his homeopathic healing methods, recommends using toothpaste as long as it does not contain sodium lauryl sulfate.
Some toothpastes contain soap ingredients, such as sodium lauryl sulfate, that can agitate cold sores, notes TheraBreath. These toothpastes can actually lead to canker sore formation in some people.