Drooling at the right corner of the mouth may be a precursor of diseases such as facial nerve paralysis and cerebrovascular disease, but it may also be due to physiological factors such as incorrect sleeping position. 1. Facial nerve palsy: Facial muscle paralysis due to damage to the facial nerve, causing the corners of the mouth on the sick side to be crooked and drooling. 2. Cerebrovascular disease: Cerebral infarction or cerebral hemorrhage will cause central facial paralysis and drooling symptoms, which may result in drooling on the right side of the mouth. The patient may also have slurred speech, the corner of the mouth to one side or one side of the limb movement inflexibility, etc., should be timely hospital consultation. 3. Physiological factors: due to incorrect sleep posture, in the right lateral position or lying on the stomach when the corner of the mouth is under pressure, lips open caused by drooling. Patients should change the bad sleep position, the general symptoms will gradually improve. If the right corner of the mouth drooling may also have other reasons, such as the symptoms continue to be unrelieved, should be timely diagnosis and treatment, so as not to delay the condition.