Doxycycline Hydrochloride Enteric Capsules does not treat mouth ulcers, mainly treats mycoplasma and chlamydia infections, and has some therapeutic effect on periodontal disease. Mouth ulcers are mainly treated with local anti-inflammatory and healing drugs. Doxycycline Hydrochloride Enteric Capsules is a tetracycline drug that can be used to treat infections caused by Rickettsia, Mycoplasma and Chlamydia. For oral diseases, it has a certain inhibitory effect on the causative organisms of periodontal disease, but it cannot treat mouth ulcers. Mouth ulcers are usually treated with topical anti-inflammatory medications and medications that promote healing, commonly used as films and lozenges. In addition, many mouth ulcers are caused by vitamin deficiencies or localized irritation, and require vitamin supplementation or removal of localized irritation to promote healing. Medications should be used under the direction of a physician.