In the oral ulcer wound on the external application of cephalosporins is ineffective, the current common ulcers are as follows: a. Recurrent Aphthous ulcers, the etiology is still unclear, there are obvious individual differences, domestic and foreign scholars believe that it may be the result of the combined effect of a variety of factors, there is no clear evidence that the recurrent Aphthous ulcers are bacterial infections, so the application of cephalosporins is ineffective. It is widely believed that it may be related to immune factors, genetic factors, systemic systemic diseases, or geographic environment, social environment, nutritional status, free radicals and other factors. Secondly, traumatic ulcers are caused by local irritants repeatedly rubbing the oral mucosa, and bacterial infections are also unrelated, so there is no need for topical cephalosporins. On the ulcer surface can be used topically iodized glycerin, ice boron powder, watermelon cream, cidadeine iodine tablets, even without drug treatment, can be healed naturally.