The redness of the oral mucosa all the time may be related to physiologic factors, or it may be due to oral erythema, herpes stomatitis and other causes. 1. Physiological factors: If you have eaten too hot food in the near future, causing the oral mucosa to be burned, it may cause the oral mucosa to become red all the time. This is a normal physiological phenomenon, along with the passage of time, can make the oral mucosa redness phenomenon gradually disappear on its own, without special intervention. 2. Oral erythema: this disease belongs to a kind of oral mucous membrane disease, which is a kind of precancerous lesion, and it can lead to red plaques on the oral mucous membrane of the patient, thus causing the oral mucous membrane to be red all the time, and most of the patients don’t have obvious self-conscious symptoms, and a few of the patients can have a burning pain in the affected area. 3. Herpetic stomatitis: the disease is usually caused by herpes simplex virus infection of the skin and mucous membrane disease, which occurs in the face, perioral skin and oral mucous membrane, which may cause the oral mucous membrane is always red, but also can be accompanied by blisters, burning pain and other symptoms. The redness of the oral mucosa may also be caused by other reasons. If the symptoms persist or are accompanied by other discomforts, you should consult a doctor as soon as possible.