Dry mouth without tears may be caused by dry syndrome, may also be caused by environmental factors, common causes are as follows: 1. Dry syndrome: the earliest symptom of dry syndrome is dry eyes and dry mouth, dry keratoconjunctivitis and dry mouth, which is characterized by the desire to cry without tears; always want to drink water, and drink water after talking for a while, which are all the early manifestations of dry syndrome. 2. Environmental factors: usually drink too little water, or because the air is too dry and other reasons. If the patient’s symptoms of dry mouth and dry eyes are serious, or if the symptoms persist and do not get better, he should go to the hospital in time for treatment.