The mouth becomes red and moist refers to the red part of the lips, not red and moist has many reasons, such as iron deficiency anemia, insufficient sunscreen, environmental dryness, etc., you can take general treatment and ferrous sulfate and other medications for different situations to improve. 1. Iron deficiency anemia: as the name suggests, it is a nutritional anemia caused by the lack of iron. Usually can eat some liver, animal blood food, can supplement ferrous sulfate and other oral medication. 2. Insufficient sunscreen: when sunscreen is insufficient, the lips will also appear hyperpigmentation and other conditions, so active sunscreen can make the mouth become red. 3. Environmental dryness: too dry when the mouth is prone to keratin hyperplasia, and then peeling, affecting the appearance of the lips. So strengthen the moisturizing, is conducive to the mouth to become red. There are many other ways to make the mouth moist, if necessary, you can consult a doctor, the above medication as prescribed by the doctor.