Most toothpastes on the market contain sodium lauryl sulfate. This ingredient is used to create the foaming action and is shte same ingredient that creates foam in your hair shampoo and dish soap. Some patients who suffer from mouth ulcers and canker sores may find that a toothpaste with sodium lauryl sulfate will irritate existing lesions, or may even be a cause of the ulcers. Studies are being conducted, but if you do suffer from ulcers and cankers, you may consider trying a toothpaste that does not include sodium lauryl sulfate. Just read the ingredients list and steer clear. The main difference you will notice with your new toothpaste is that you won’t get the foaming action when you brush, which just takes a little getting used to.