The feeling of a film on the mouth is considered to be related to insufficient water intake, dry air, lipitis and other factors. 1. Insufficient drinking water: If the patient has recently consumed too little water, the water intake may be too low, which may cause the cuticle of the lips to protrude, resulting in the phenomenon of the mouth feeling like a film. 2. Dry air: in the wind and sand too much or dry air environment, may be due to excessive loss of water in the lip area, lips tight when the local will appear a layer of film symptoms. 2. Lipitis: the mouth feels a layer of film, also does not exclude and lipitis, lipitis is an inflammatory disease occurring in the lips, usually chronic lipitis is more common, with repeated dry lips flaking, itching, swelling, oozing as the main feature, consider and sunlight exposure, climate change, spicy food and other factors. If the symptoms cannot be relieved, it is recommended that the patient seeks medical examination to clarify the cause of the disease and choose the appropriate way of treatment.