A foggy head and feeling dizzy may be caused by diseases such as encephalitis, cerebral blood supply deficiency and otolithiasis. 1. Encephalitis: Encephalitis is an infectious disease of the central nervous system caused by pathogens such as viruses, bacteria, fungi or parasites. Encephalitis can lead to symptoms such as headaches and a foggy feeling in the head. 2. Insufficient blood supply to the brain: It is due to the reduction of blood inflow to the brain and insufficient pumping of blood from the heart, etc. When insufficient blood supply to the brain occurs, the patient will suffer from a series of symptoms such as dizziness, headache, insomnia, forgetfulness, and memory loss. 3. Otolithiasis: Otolithiasis is a form of vertigo caused by a change in head position due to the direction of gravity or by other diseases. When the head moves to a particular position, transient vertigo occurs due to vestibular dysfunction. Therefore, it can lead to dizziness in the head. Dizziness may also be caused by high blood pressure or insufficient blood supply to the vertebral basilar artery, etc. If the symptom of dizziness persists and is not relieved, it is necessary to consult a doctor in time for treatment.