Numbness in the upper jaw of the mouth may be caused by improper diet, oral ulcers, oral cancer and so on. 1. Improper diet: If you eat too cold, too hot, spicy or irritating food, it may stimulate the nerves in the palate, thus numbness in the upper jaw of the mouth occurs. 2. Mouth ulcers: they may be caused by infection, heredity, mental stress and so on. When the oral mucosa of the palate is broken, it may stimulate the sensory nerves, which may cause numbness of the palate. 3. Oral cancer: its cause is not completely clear, and it may be related to tobacco, ethanol, poor oral hygiene and so on. When oral tumor invades the nerves of the palate, numbness can occur. It is recommended that patients with numbness of the palate should go to the hospital in time and follow the doctor’s instruction for treatment to avoid delaying their condition.