What is dry throat? Dry throat is a rough, scratchy, sometimes itchy feeling in the throat. The most common cause of dry throat is drying out of the mucus membranes, often as a result of exercise, sleeping with your mouth open, breathing through your mouth, living in a dry environment, or simply not drinking enough fluids. Dry throat is also caused by tobacco or marijuana use, voice strain, vomiting, excessive coughing, throat inflammation, allergies, and, in rare cases, cancers of the throat and esophagus. Seek prompt medical care if you have white patches on your tonsils (which may be a sign of strep throat or mononucleosis), a persistent or mucus-producing cough, white patches and redness on your tongue or in your mouth that will not go away, fever, or if you have a feeling of something stuck in the throat that will not go away.