 Sodium lauryl sulphate ( SLS ) , a detergent present in some brands of toothpaste and other oral healthcare products , may produce oral ulceration in some individuals . It has been shown that aphthous stomatitis is more common in people using toothpastes containing SLS , and that some reduction in ulceration occurs when a SLS @-@ free toothpaste is used . Some have argued that since SLS is almost ubiquitously used in oral hygiene products , there is unlikely to be a true predisposition for aphthous stomatitis caused by SLS . 
