Sudden dizziness and tinnitus may be caused by anemia, high blood pressure, low blood sugar and other reasons. 1. Anemia: In general, after anemia, the oxygen carrying capacity of the blood will be reduced to a certain extent, the degree of blood volume decline, the speed of anemia and the compensatory capacity of the blood circulation and respiratory system may lead to dizziness, tinnitus, fatigue, and so on, and the more prominent sign is pallor. 2. High blood pressure: high blood pressure causes dizziness and tinnitus may be caused by prolonged overwork, often stay up late, often like to eat some greasy food, low immunity and insufficient blood supply to the brain. 3. Hypoglycemia: a long time not to eat breakfast or daily diet is not reasonable, may induce hypoglycemia, when the acute attack of hypoglycemia can appear suddenly dizziness, tinnitus, fatigue and sleepiness. It is recommended that patients with sudden dizziness and tinnitus actively seek medical attention and complete relevant examinations to clarify the diagnosis and cause of the disease.